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    • http://www.webmd.com/hw/health_guide_atoz/hw6580.asp A-Z Health Guide from WebMD: Medical Tests Urine Test Test OverviewA urine test measures several different components of urine, a waste product made by the kidneys. A routine urinescreening test may be done to help find the cause for many types of symptoms. The test can provide information aboutyour overall health and clues to many conditions.The kidneys remove waste material, minerals, fluids, and other substances from the blood for elimination in theurine. Therefore, urine can contain hundreds of different bodily waste products. Many factors, such as diet, fluid intake,exercise, and kidney function, affect what is in your urine.More than 100 different tests can be done on urine. A routine urinalysis usually includes the following tests.  Color. Many factors affect urine color, including fluid balance, diet, medications, and disease. The intensity of the color generally indicates the concentration of the urine; pale or colorless urine indicates that it is dilute, and deep yellow urine indicates that it is concentrated. Vitamin B supplements can turn urine bright yellow. Reddish brown urine may be caused by certain medications; by blackberries, beets, or rhubarb in the diet; or by the presence of blood in the urine.  Clarity. Urine is normally clear. This test determines the cloudiness of urine, also called opacity or turbidity. Bacteria, blood, sperm, crystals, or mucus can make urine appear cloudy.  Odor. Urine usually does not smell very strong, but has a slightly "nutty" (aromatic) odor. Some diseases can cause a change in the normal odor of urine. For example, an infection with E. coli bacteria can cause a foul odor, while diabetes or starvation can cause a sweet, fruity odor.  Specific gravity. This measures the amount of substances dissolved in the urine. It also indicates how well the kidneys are able to adjust the amount of water in urine. The higher the specific gravity, the more solid material is dissolved in the urine. When you drink a lot of liquid, your kidneys should produce greater- than-normal amounts of dilute urine (low specific gravity). When you drink very little liquid, your kidneys should make only small amounts of concentrated urine (high specific gravity).  pH. The pH is a measure of how acidic or alkaline (basic) the urine is. A urine pH of 4 is strongly acidic, 7 is neutral (neither acidic nor alkaline), and 9 is strongly alkaline. Sometimes the pH of urine may be adjusted by certain types of treatment. For example, efforts may be made to keep urine either acidic or alkaline to prevent formation of certain types of kidney stones.  Protein. Protein is normally not detected in the urine. Sometimes a small amount of protein is released into the urine when a person stands up (this condition is called postural proteinuria). Fever, strenuous exercise, normal pregnancy, and some diseases, especially kidney disease, may also cause protein in the urine.  Glucose. Glucose is the type of sugar usually found in blood. Normally there is very little or no glucose in urine. However, when the blood sugar level is very high, as in uncontrolled diabetes, it spills over into the urine. Glucose can also be present in urine when the kidneys are damaged or diseased.  Nitrites. Bacteria that cause a urinary tract infection (UTI) produce an enzyme that converts urinary nitrates to nitrites. The presence of nitrites in urine indicates a UTI.  Leukocyte esterase (WBC esterase). Leukocyte esterase detects leukocytes (white blood cells [WBCs]) in the urine. The presence of WBCs in the urine may indicate a urinary tract infection.  Ketones. When fat is broken down for energy, the body produces by-products called ketones (or ketone bodies) and releases them into the urine. Large amounts of ketones in the urine may signal a dangerous condition known as diabetic ketoacidosis. A diet low in sugars and starches (carbohydrates), starvation, or prolonged vomiting may also cause ketones in the urine.  Microscopic analysis. In this test, urine is spun in a centrifuge so the solid materials (sediment) settle out. The sediment is spread on a slide and examined under a microscope. Types of materials that may be found include: o Red or white blood cells. Normally blood cells are not found in urine. Inflammation, disease, or injury to the kidneys, ureters, bladder, or urethra can cause blood in urine. Strenuous exercise (such as running a marathon) can also cause blood in urine. White blood cells are often a sign of infection, cancer, or kidney disease. o Casts. Some types of kidney disease can cause plugs of material (called casts) to form in tiny tubes in the kidneys. The casts can then get flushed out into the urine. Casts can be made of different types of material, such as red or white blood cells, waxy or fatty substances, or protein. The type of cast can provide clues about the type of kidney disease that may be present.
    • o Crystals. Healthy people often have only a few crystals in their urine. However, a large number of crystals, or the presence of certain types of crystals, may indicate kidney stones or a problem with how the body is using food (metabolism). o Bacteria, yeast cells, or parasites. Normally there are no bacteria, yeast cells, or parasites in urine. Their presence can indicate an infection.Why It Is DoneA urine test may be done:  To screen for a disease or infection of the urinary tract. Symptoms that may lead to a urine test include discolored or foul-smelling urine, pain during urination, difficulty urinating, flank pain, blood in the urine (hematuria), or fever.  To monitor the treatment of certain conditions such as diabetes, kidney stones, a urinary tract infection (UTI), hypertension, or some types of kidney or liver disease.  As part of a routine physical examination.How To PrepareDo not eat foods that can discolor the urine, including blackberries, beets, and rhubarb. Do not exercise strenuouslybefore a urine sample is taken.Tell your health professional if you are menstruating or within a few days of starting your menstrual period. Your healthprofessional may want to postpone the urine test, depending on the suspected problem.Because certain medications can discolor the urine, your health professional may instruct you to stop taking themedications prior to the test. Medications that can discolor the urine include vitamin B, phenazopyridine (Pyridium),rifampin, and phenytoin (Dilantin). Be sure to tell your health professional if you are taking diuretics, which may affectthe test results.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneA routine urine test can be done in your health professionals office, clinic, or lab. You may also be asked to collect aurine sample at home and bring it with you to the office or lab for testing.Clean-catch midstream urine collectionThis collection method prevents contamination of the sample.  Wash your hands to make sure they are clean before collecting the urine.  If the collection container has a lid, remove it carefully and set it down with the inner surface up. Avoid touching the inside of the container with your fingers.  Clean the area around your genitals. o A man should retract the foreskin, if present, and clean the head of his penis thoroughly with medicated towelettes or swabs. o A woman should spread open the folds of skin around her vagina with one hand, then use her other hand to clean the area around her vagina and urethra thoroughly with medicated towelettes or swabs. She should wipe the area from front to back to avoid contaminating the urethra with bacteria from the anus.  Begin urinating into the toilet or urinal. A woman should continue to hold apart the folds of skin around the vagina while she urinates.  After the urine has flowed for several seconds, place the collection container into the stream and collect about 2 fl oz(59 mL) of this ―midstream‖ urine without interrupting the flow.  Avoid touching the rim of the container to your genital area, and avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.  Finish urinating into the toilet or urinal.  Carefully replace the lid on the container and return it to the lab. If you are collecting the urine at home and cannot get it to the lab within an hour, refrigerate it.
    • Double-voided urine sample collectionThis collection method reflects the type of urine your body is producing right now.  Empty your bladder by urinating into the toilet or urinal. Do not collect any of this urine.  Drink a large glass of water and wait about 30 to 40 minutes.  Follow the instructions above for collecting a clean-catch urine sample.The urine sample is then sent to a lab for analysis.How It FeelsCollecting a urine sample does not normally cause any discomfort.RisksThere are no risks associated with collecting a urine sample.ResultsA urine test measures several different components of urine, a waste product made by the kidneys. Normal results mayvary from lab to lab.Color Normal: Pale to dark yellow Abnormal: Many foods and medications can affect the color of the urine. Colorless urine may be caused by conditions such as long-term kidney disease or uncontrolled diabetes. Dark yellow urine can be caused by conditions such as dehydration. Reddish urine can be caused by blood in the urine.Clarity Normal: Clear Abnormal: Cloudy urine can be caused by pus (white blood cells), blood (red blood cells), sperm, bacteria, yeast, crystals, mucus, or a parasite infection (such as trichomoniasis).Odor Normal: Slightly "nutty" (aromatic) odor Abnormal: Some foods (such as asparagus), vitamins, and antibiotics (such as penicillin) can cause urine to develop an unusual odor. A sweet, fruity odor may be caused by uncontrolled diabetes. A urinary tract infection (UTI) can cause a foul odor. Urine that smells like maple syrup can indicate maple syrup urine disease, a condition caused by the bodys inability to break down certain amino acids.Specific Normal: 1.005–1.035gravity Abnormal: Abnormally high specific gravity indicates very concentrated urine, which may be caused by not drinking enough liquid, loss of too much liquid (excessive vomiting, sweating, or diarrhea), or substances (such as sugar or protein) in the urine. Abnormally low specific gravity indicates dilute urine, which may be caused by drinking excessive amounts of liquid, severe kidney disease, or the use of diuretics.pH Normal: 4.5–8.0 Abnormal: Some foods (such as citrus fruit and dairy products) and medications (such as antacids) can affect urine pH. A high (alkaline) pH can be caused by prolonged vomiting, a kidney disease, some urinary tract infections, and asthma. A low (acidic) pH may be a sign of severe lung disease (emphysema), uncontrolled diabetes, aspirin overdose, prolonged diarrhea, dehydration, starvation, drinking an excessive amount of alcohol, or drinking antifreeze (ethylene glycol).Protein Normal: None Abnormal: Protein in the urine usually indicates kidney damage or disease that can be caused by conditions such as an infection, cancer, high blood pressure, diabetes, systemic lupus erythematosus (SLE), or glomerulonephritis. Protein in the urine can also be caused by heart failure, leukemia, poison (lead or mercury
    • poisoning), or a condition during pregnancy that results in high blood pressure (preeclampsia).Glucose Normal: None Abnormal: Intravenous (IV) fluids can cause the presence of glucose in the urine. Excess glucose in the urine is often caused by uncontrolled diabetes. Other conditions that may cause glucose in urine include an adrenal gland problem, liver damage, brain injury, certain types of poisoning, and certain types of kidney diseases that decrease their ability to reabsorb glucose from the urine. Healthy pregnant women can have glucose in their urine which is normal during pregnancy.Ketones Normal: None Abnormal: Ketones in the urine can indicate poorly controlled diabetes, a very low-carbohydrate diet, starvation (including disorders that result in poor nutrition such as anorexia nervosa or bulimia), alcoholism, or poisoning from drinking rubbing alcohol (isopropanol). Ketones are often found in the urine when a person does not eat (fasts) for 18 hours or longer. This may occur when a person is sick and avoids food or vomits for an extended period of time. Low levels of ketones are sometimes found in the urine of a healthy pregnant woman.Microscopic Normal: Very few or no red or white blood cells or casts are seen. No bacteria, yeast cells, oranalysis parasites are present. A few crystals are usually normal. Abnormal: Red blood cells in the urine may be caused by kidney or bladder injury, kidney stones, a urinary tract infection (UTI), inflammation of the kidneys (glomerulonephritis), a kidney or bladder tumor, or systemic lupus erythematosus (SLE). White blood cells (pus) in the urine indicate a urinary tract infection, bladder tumor, inflammation of the kidneys, systemic lupus erythematosus (SLE), or inflammation under the foreskin of the penis or in the vagina. Depending on the type, casts can indicate inflammation or damage to the tiny tubes in the kidneys, poor blood supply to the kidneys, metal poisoning (such as lead or mercury), heart failure, or a bacterial infection. Excessive amounts of crystals, or the presence of certain types of crystals, can indicate kidney stones, damaged kidneys, or problems with metabolism. Some medications and certain types of urinary tract infections can also increase the number of crystals in urine. Bacteria in the urine indicate a urinary tract infection (UTI). Yeast cells or parasites (such as the parasite that causes trichomoniasis) can indicate an infection of the urinary tract.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Blood from a womans menstrual period.  Medications, such as diuretics or high doses of vitamin C (ascorbic acid) taken with certain antibiotics (such as tetracycline).  Some antibiotics, such as erythromycin and trimethoprim (Trimpex).  Contrast material used in an X-ray test.What To Think About  Some urine tests can be done using a home test kit. For more information, see the medical test Ketones or Home Test for Urinary Tract Infections.  In some cases, the amount (volume) of urine produced in 24 hours may be measured. Most adults produce 1.3 qt(1.2 L) to 1.6 qt(1.5 L) of urine each day, with a normal range of about 1 qt(1 L) to 2 qt(2 L) per day. Children produce about 0.3 qt(0.3 L) to 1.6 qt(1.5 L) per day.  Other substances that may be measured during a urine test include: o Bilirubin, a compound formed by the breakdown of red blood cells and normally eliminated from the body in stool. Bilirubin is not normally found in urine. If it is present, it usually means the liver is damaged or the flow of bile from the gallbladder is blocked. For more information, see the medical test Bilirubin. o Urobilinogen, a compound formed by the breakdown of bilirubin and eliminated from the body mostly in stool. Only small amounts of urobilinogen are normally found in urine. Urobilinogen in urine can be a sign of liver disease (cirrhosis, hepatitis) or blockage of the flow of bile from the liver or gallbladder.
    • o Bence Jones protein, an abnormal protein found in the urine of about 50% of people with a rare type of cancer called multiple myeloma. A urine test is usually done when multiple myeloma is suspected. The protein test done during a routine urine test does not usually detect Bence Jones protein.  Collecting a urine sample from a small child or baby may be done by using a special plastic bag with tape around its opening. The bag is attached around the childs genitals until he or she urinates (usually within an hour). Then the bag is carefully removed. To collect a urine sample from a very sick baby, a health professional may insert a urinary catheter through the urethra or a needle through the babys abdomen directly into the bladder (suprapubic tap).  To reduce the chance of contaminating the urine sample with bacteria (other than the bacteria causing the infection), a health professional may collect a urine sample by inserting a thin flexible tube (called a urinary catheter) through the urethra into the bladder. Catheterization is sometimes done to collect urine from a person in the hospital who is very ill or unable to provide a clean-catch sample (such as a child). This method reduces the risk that the sample will be contaminated, but it may occasionally cause a urinary tract infection (UTI).  If an abnormal result is found during a urine test, additional tests may be done, such as a urine culture, X- ray of the kidneys (intravenous pyelography or IVP), or cystoscopy. For more information, see the medical tests Urine Culture, Intravenous Pyelogram (IVP), and Cystoscopy.CreditsAuthor Jan Nissl, RN, BSEditor Susan Van Houten, RN, BSN, MBAAssociate Editor Tracy LandauerPrimary Medical Reviewer Patrice Burgess, MD - Family MedicineSpecialist Medical Reviewer Philip Belitsky, MD, FRCSC - UrologyLast Updated December 7, 2004 UrinalysisUrinalysis begins with a macroscopic examination of the urine which describes the color and clarity ofthe urine. Many factors affect urine color including fluid balance, diet, medications and disease. Thefollowing table includes a list of the most common causes of abnormal urine coloration. Color Pathologic Causes Food & Drug Causes Cloudy Phosphorus, pyuria, chyluria, Diet high in purine-rich foods causing lipiduria, hyperoxaluria uricosuria Brown Bile pigments, myoglobin Fava beans, Levodopa, metronidazole (Flagyl), nitrofurantoin, anti-malarial drugs Brownish- Bile pigments, melanin, Cascara, levodopa, methyldopa, Senna Black methemoglobin Green or Pseudomonas UTI, biliverdin Amitriptyline, indigo, carmine, IV cimetidine Blue (Tagamet), IV promethazine (Phenergan), methylene blue, triamterene (Dyrenium) Orange Bile pigments Phenothiazines, phenazopyridine (Pyridium) Red Hematuria, hemoglobinuria, Beets, blackberries, rhubarb, Phenolphthalein, myoglobinuria, porphyria rifampin Yellow Concentrated urine Carrots, Cascara
    • Urine samples are initially screened with dipsticks. Performing microscopic analysis on only dipstickpositive urine samples is cost effective when the patient population being tested has a low incidence ofpotential disease. Numerous studies have determined that 6 to 20% of patients with urine sedimentabnormalities are missed by this testing strategy. However, most of the missed cases are clinicallyinsignificant and are often due to contaminating bacteria multiplying after urine collection. Urinedipsticks are plastic strips with attached reagent pads for pH, protein, glucose, ketone, bilirubin,urobilinogen, blood, nitrite, and leukocyte esterase. The principle and performance of each dipstick testis summarized below.pHThe test is based on a double indicator method (methyl red and bromthymol blue) that covers the entirerange of urine pH. Colors range from orange through yellow and green to blue. pH should be measuredin fresh urine and read quickly.The pH of urine is an indication of the kidneys ability to maintain a normal plasma pH. Metabolismproduces acids that are excreted by the lungs and kidneys. The average adult urine pH varies between 5and 8. A diet high in protein produces a more acid urine, while a vegetarian diet often produces a pHgreater than 6. Heavy bacterial growth may cause an alkaline shift in urine pH by converting urea toammonia. Pigmented urine can interfere with pH readings.Bacterial contaminants, blood in the urine and contamination by genital secretions can alter urine pH.ProteinThe protein test is based on a change in color of a pH indicator (e.g. tetrabromophenol blue) in thepresence of varying concentrations of protein when the pH is held constant. The reagent pad containsthe indicator and a buffer that holds the pH of the pad at approximately 3. Yellow indicates undetectableprotein. The color of positive reactions ranges from yellow-green to green to green-blue. The accuracy ofthis test depends on having urine that is slightly acidic. Dipsticks can detect protein concentrations aslow as 5 to 30 mg/dL. Urine protein concentrations are reported as 30, 100, 300, or 2000 mg/dL.This test is optimized to detect albumin and is less sensitive in detecting globulins. Dipsticks do notdetect beta-2- microglobulin or immunoglobulin light chains. Standard urine dipsticks are much lesssensitive at detecting urine albumin than other assays. Dipsticks do not detect microalbuminuria. Sensitivity Method Typical Detection Limit(mg/dL) (Relative to Urine Dipstick) Dipstick Protein 18 1 Spectrophotometric Urine Protein 6 3X more sensitive Immunoassay for Urine Albumin 0.3 60X more sensitiveDipstick testing is useful only when urinary protein exceeds 300 to 500 mg/day or albumin exceeds 10to 20 mg/day.The major cause of a false positive urine protein is a highly alkaline sample. False positive reactions canalso be caused by contamination with quaternary ammonium compounds (zepharin, chlorhexidine) usedto clean the skin for a clean catch urine. Excessive contact with urine may wash out the bufferingsystem and lead to a false positive result. Confirmatory tests only need to be performed on those urinesamples with positive protein and a pH of 7.5 or greater.Proteinuria can have many causes. Postural proteinuria occurs in 3 to 5% of healthy adults and ischaracterized by the presence of protein in the urine during the day but not the night. Strenuousexercise, fever, and exposure to extreme heat or cold, pregnancy, eclampsia, shock, and CHF causefunctional proteinuria. Hematologic malignancies, such as multiple myeloma, may produce excessimmunoglobulin that is excreted in the urine. Renal diseases are a common source of proteinuria.Approximately 25% of urine specimens containing bacteria will have a positive protein reaction as theonly positive dipstick reaction. The esterase reagent is sensitive to 15 leukocytes per hpf, but the protein
    • reagent is sensitive to 6 leukocytes per hpf.GlucoseThe dipstick test is based on a double enzyme method employing glucose oxidase and peroxidase. Colorchange ranges from green to brown. Small amounts of glucose (< 15 mg/dL) are normally excreted bythe kidney, which is below the 75 mg/dL lower limit of detection of dipsticks, Glucose oxidase is specificfor glucose and does not react with lactose, galactose, fructose, or reducing metabolites of drugs.Glucose is reported as 100, 250, 500, 1000, or >1000 mg/dL.Urine specific gravity and temperature may affect test reactivity. High urine specific gravity can reducecolor development. Urine should be at room temperature before the test is performed to obtain optimumsensitivity. False positive reactions rarely occur, but may be produced by strong oxidizing cleaningagents. Beta lactam antibiotics such as the penicillins, cephalosporins, carbapenems, and monobactamscan cause false positive reactions. Massive amounts of ascorbic acid (vitamin C), salicylates or levodopacan decrease the sensitivity of the test.Negative urine samples from pediatric patients under the age of one should be confirmed with a copperreduction method, such as Clinitest, to detect galactose or lactose. Confirmation only needs to beperformed once on a patient.Glucosuria usually occurs when the blood glucose level exceeds 180 mg/dL. Glucosuria most commonlyoccurs in patients with diabetes, infections, myocardial infarction, liver disease, and obesity. Thiazides,corticosteroids, and birth control pills may precipitate glucosuria.KetonesDipsticks use the nitroprusside reaction to test for acetoacetic acid. They are less sensitive to acetoneand do not detect beta-hyroxybutyrate. The typical diabetic patient with ketoacidosis usually excretes78% beta-hyroxybutyrate, 20% acetoacetate, and 2% acetone. The reaction of acetoacetic acid withnitroprusside results in the development of color ranging from buff pink to shades of purple. Colorreactions are categorized as trace, small, moderate and large that correspond to ketone concentrationsof 5, 15, 40 to 80 and 80 to 160 mg/dL of urine, respectively. Dipsticks reliably detect ketoneconcentrations of 40 mg/dL or more, so moderate and large readings do not need to be confirmed. Traceand small readings should be confirmed by using Acetest. The detection level for Acetest tablets is 20mg/dL. The presence of ketonuria does not signal the need to do further microscopic evaluation.Normally, urine contains < 2 mg/dL of acetoacetic acid, which is not detectable. A healthy individualmay have detectable ketones if he/she has been fasting, strenuously exercising, or is pregnant. Ketonesare also detected in children consuming high fat diets. Ketonuria is commonly seen in hospitalizedpatients due to fasting. Ketones are clinically significant only in the presence of urine glucose. Drugswith free sulfhydryl groups such as penicillamine, N-acetylcysteine, BAL and ACE inhibitors (captopriland enalapril) cause false positive reactions.Ketones are volatile and evaporate from the specimen with time. False negative results can occur withold urine samples. The reagent pads are extremely sensitive to moisture and may become non-reactiveafter exposure to humid room air for a few hours.BloodThe dipstick test for blood is based on the peroxidase-like activity of hemoglobin. Red cells are lysed oncontact with the strip, allowing free hemoglobin to catalyze the liberation of oxygen from organicperoxide. Tetramethylbenzidine is oxidized, producing a color change from orange to green-blue. Ifintact red cells do not lyse, they may produce speckles on the pad. The sensitivity of dipsticks forhemoglobin is 0.015 to 0.062 mg/dL. This concentration corresponds to 5 to 21 RBCs/uL or 1 to 4RBCs/hpf of concentrated urine sediment.The reference range for RBCs in normal urine is 0-3 RBC/hpf in males and 0-12 RBCs/hpf in femaleswhen concentrated urine sediment is examined. This range corresponds to a concentration of 3 to 20RBCs/uL of urine. Dipstick sensitivity extends into the reference range. Therefore, trace to 1+ readingmay be obtained on urine from as many as 3% of healthy individuals.In healthy individuals, fewer than 1000 red cells are excreted in the urine per minute. When 3000 to4000 red cells are excreted per minute, 2 to 3 red cells will be seen per high power field, indicatingmicroscopic hematuria. Gross hematuria occurs when more than 1 million red cells are excreted perminute. Hematuria can be due to lesions within the GU tract involving the kidneys, ureters, bladder,prostate, or urethra. The most common disorders include cancer, kidney stones, renal disease, urinarytract infection, and benign prostatic hyperplasia. Transient hematuria can result from menstruation, viral
    • illnesses, strenuous exercise, and mild trauma. Anticoagulant therapy and chemotherapy may also causehematuria. No etiology can be determined in approximately 45% of cases of microscopic hematuria.A positive dipstick test for blood does not tell whether the reaction is due to red cells, red cell casts,hemoglobin casts, or myoglobin. Many conditions can lead to discrepant dipstick and microscopicfindings. Any situation that causes red cell hemolysis will give a positive dipstick and negativemicroscopic result. Urine should be tested shortly after collection because red cell lysis may occur as thesample ages, if the pH is alkaline, or if the specific gravity is 1.010 or less. Bacterially contaminatedurine specimens may contain sufficient peroxidase activity to produce a false positive reaction. Falsepositive reactions can also be caused by vegetable peroxidase. False Positive Dipstick False Negative Dipstick Myoglobin Dipsticks exposed to air Oxidizing agents - bleach, detergent, iodine RBCs settle out & urine not mixed Bacterial peroxidase Ascorbic acid (high concentration) Vegetable peroxidase Formaldelhyde (preservative tablets) Betadine High specific gravity Very high protein Urine pH <5.1 High nitrite from UTI Captopril (Capoten)BilirubinThe bilirubin dipstick test detects conjugated bilirubin and has a sensitivity of 0.5 to 1.0 mg/dL. This testis based on the binding of conjugated bilirubin to diazotized salts fixed in the test pad in a strong acidicenvironment to produce a colored compound that is various shades of tan or magenta. Positive dipsticktests are confirmed with the Ictotest. Normal adult urine contains about 0.02 mg/dL of bilirubin, which isnot detectable by even the most sensitive methods. Confirmation of positive dipstick bilirubin results ismost valuable when the urine specimen is pale yellow.Ictotest is a tablet test that uses a similar chemical reaction but a different test environment. Urine isplaced on an absorbent test mat that captures substances within the urine. The reagent tablet is thenplaced on top of the absorbed urine and water is added to the tablet. The water dissolves the soliddiazonium salt and acid in the tablet so that they run onto the mat. The reaction of conjugated bilirubinwith the diazonium salt in the acid environment results in the formation of a blue ring around thedissolving tablet. The sensitvity of the tablet test is 0.05 to 0.1 mg/dL, which is about 10 times moresensitive than the dipstick test. The tablet test is also more specific than the dipstick test for bilirubinand its primary use is the detection of false positive dipstick reactions. Since the urine is placed on themat first in the tablet test, abnormal pigments due to medications or blood metabolites can be detectedbefore the chemical reaction ensues. Other interfering substances are washed through the mat and donot come into contact with the diazonium salt. Also, because the reaction product is blue rather than tanor magenta, fewer interpretation problems are encountered. Examples of medications that produce falsepositive dipstick and negative Ictotest results include rifampin, phenazopyridium (Pyridium), andnonsteroidal antiinflammatory agents (etodolac, mefenamic acid and flufenamic acid).Bilirubin and urobilinogen tests are valuable in detecting hemolysis, hepatic dysfunction, and biliaryobstruction. The results of these two tests should be interpreted together. Bilirubin is unstable andrapidly decomposes during exposure to light. False negative reactions are common if urine is not testedshortly after collection. Chlorpromazine (Thorazine) and selenium can produce false negative results.UrobilinogenMost dipsticks use para-dimethylaminobenzaldehyde in a strongly acid medium to test for urobilinogen.A positive reaction produces a pink-red color. Urobilinogen is normally present in urine at concentrationsup to 1.0 mg/dL. A result of 2.0 mg/dL represents the transition from normal to abnormal. False positive
    • results can be caused by medications such as para-aminosalicylic acid, antipyrine, chlorpromazine,phenazopyridine, phenothiazine, sulfadiazine, and sulfonamide. High nitrite concentrations can causefalse negative reactions. Pigmented urine can interfere with detection of urobilinogen.Conjugated bilirubin is normally excreted into the bowel where bacteria metabolize it to urobilinogen.Urobilinogen is partially reabsorbed from the gut and excreted in the urine. A positive test indicatesincreased bilirubin delivery to the gut. Hepatitis produces positive urine bilirubin and urobilinogen. Biliarytract obstruction results in positive urine bilirubin but negative urobilinogen. Hemolytic anemia causesnegative urine bilirubin and positive urobilinogen. Disease Urobilinogen Bilirubin Healthy Normal Negative Icteric liver disease Increased Positive Biliary obstruction Absent Positive Hemolytic anemia Increased NegativeLeukocyte EsterasePyuria (the presence of leukocytes in the urine) can be detected using the leukocyte esterase reagentstrip test. The assay is based on the chemi¬cal detection of esterases, which are enzymes containedwithin the azurophilic granules of polymorphonuclear leukocytes. Esterase level is directly proportional tothe number of leukocytes present in a urine sample. The basis of the chemical reaction is the hydrolysisof an ester to form an aromatic alcohol and acid. The aromatic compound combines with a diazoniumsalt to form an azo-dye that changes to purple. Color intensity read at two minutes is proportional to thenumber of granulocytes in a sample. Positive results are reported semiquantitatively as trace, 1+, 2+, or3+. The sensitivity for Multistix reagent strips is 5 cells per high power field (hpf) to 15 cells/hpf whileChemstrip reagent strips have a sensitivity of 20 leukocytes per uL of urine. Because of this relativeinsensitivity, the absence of leukocyte esterase does not rule out urinary tract infection (UTI). A positiveesterase reaction indicates inflammation secondary to UTI or renal disease.Esterase activity from either intact or lysed granulocytes can give a positive result. Lysed granulocytesmay produce apparent discrepancies between positive dipstick results and negative microscopicexaminations. Lympho¬cytes do not produce a positive reaction. Other sources of esterase such aseosinophils, Trichomonas, or epithelial cells in vaginal fluid may give false positive results. Oxidizingagents such as bleach or colored substances can produce false positives.False negative results can be caused by high concentrations of ascorbic acid (vitamin C), albumin orother proteins (>500mg/dL), glucose (>3000 mg/dL), or ketones. Urine with high specific gravity cancause a false negative reaction because enzyme is not as readily released from crenated white bloodcells. These samples should be examined microscopically so as not to miss clinically significant pyuria.WBC clumping may prevent dispersion of leukocyte esterase and cause a false negative result. Outdatedor deteriorated dipsticks are another cause of false-negative results.Doxycycline, gentamicin and some cephalosporins reduce the reactivity of leukocyte esterase andproduce false negative results. Conversely, imipenem, meropenem, and clavulanic acid can cause falsepositive leukocyte esterase reactions.Most studies comparing the sensitivity of nitrite and leukocyte esterase tests compared to urine culturehave demonstrated that leukocyte esterase is a more sensitive indicator of UTI than nitrite.NitriteThe nitrite test is a rapid, indirect method for detec¬ting bacteriuria. The reaction principle is based onbacterial reduction of dietary nitrate, which is normally present in urine, to nitrite, which is notnor¬mally present. Nitrite reacts with para-arsanilic acid on the dipstick to form a diazonium compoundthat reacts with a benoquinoline to form a pink color. Many of the bacteria that cause UTIs have theability to reduce nitrate, including Escherichia coli, Klebsiella, Pseudomonas, Enterobacter, andCitrobacter. The optimal specimen is a freshly voided, first morning urine that has been retained in thebladder a minimum of 4 hours, per¬mitting adequate time for conversion of nitrate into nitrite by thebacterial enzymes. A positive nitrite test result indicates UTI with significant bacteri¬uria. Test
    • sensitivity has been standardized to correspond to a urine bac¬terial count of 100,000 colony formingunits/mL (CFU/mL). Color intensity is not proportional to the degree of bacteriuria; results are simplyreported as positive or negative.False positive results can be caused by colored substances in the urine (e.g. phenazopyridine) andprolonged specimen storage at room temper¬ature that allows proliferation of contaminating bacteria. Ifuri¬nalysis cannot be done within two hours after collection, specimens should be refrigerated toprevent bacterial growth.False-negative nitrite results can occur even in the presence of signif¬icant bacteriuria due to a numberof possible factors. The causative organisms may lack the reductase enzyme needed to convert nitrateto nitrite. For example, both yeast and gram positive bacteria are reductase negative. Malnourishedpatients and patients receiving intravenous feed¬ing may have insufficient dietary nitrate to promotethe chemical reaction. The duration of urine retention in the bladder may be too short (< 4 hours) tofacilitate nitrate reduction. Previous antimicrobial therapy may inhibit bacterial metabolism. In thepresence of high numbers of bacteria, nitrite may be further reduced to nitrogen, which is not detected.High concentrations of ascorbic acid or urobilinogen can inhibit the chemical reaction. Of course,outdated or deteriorated dipsticks can also yield false-negatives. Microscopic examination of urinesediment or urine culture should be performed, even with negative nitrite, when clinical symptomssuggest UTI.Vitamin C is a strong reducing agent and interferes with a number of dipstick tests. An evaluation of4379 urinalysis specimens from outpatients in a single laboratory revealed that 23% containedmeasurable vitamin C. An oral dose of 100 mg of vitamin C caused falsely negative dipstick tests forblood, glucose and leukocyte esterase in urine samples tested within 4 hours of ingestion. Vitamin Cconsumption is a likely cause of discrepancies between urine dipstick and microscopic analysis.Specific GravityThe specific gravity of a solution is the ratio of the mass per unit volume of the solution to the mass perunit volume of distilled water. It is a relative measure by weight of the amount of dissolved urinarysolutes. All urine contains some solutes and will always have a specific gravity higher than pure water(1.000). Normally, an adult should be able to concentrate the urine to a specific gravity of 1.016 to1.022. A first morning urine with a specific gravity of 1.023 or higher after overnight fluid deprivationindicates normal renal concentrating capacity.The dipstick specific gravity test is based on the apparent pKa change of polyelectrolytes in relation toionic concentration. In the presence of an indicator, colors range from deep blue-green in urine of lowionic concentration through green and yellow-green in urines of increasing ionic concentration.Diabetes mellitus is associated with increased urinary volume and elevated specific gravity due tourinary glucose, which increases the solute content.Diabetes insipidus results in a large urinary volume with low specific gravity. Hyposthenuria means apersistently low urine specific gravity of < 1.007.Renal tubular disease is often manifested early by a loss of concentrating capacity of the kidneys;specific gravity is < 1.018. Later in the disease process, the capacity to dilute the urine is lost and thepatient can only produce isothenuric urine with a fixed specific gravity of 1.010.The kidneys cannot concentrate urine to a specific gravity of >1.035. Specific gravity readings greaterthan 1.035 by refractometer, accompanied by normal specific gravity by reagent strips, usually containhigher molecular weight solutes such as glucose, protein, radiopaque contrast media or drugs. Organiciodides in contrast media such as meglumine diatrizoate (Renograffin, Hypaque) may be seen in theurine sediment for a brief time after injection of the dye. The crystals resemble cholesterol crystals.Reference RangeDipstick reference ranges are summarized in the following table: Analysis Reference Value If positive, reported as: Specific gravity 1.003 - 1.030 Number Blood Negative Small, moderate, large
    • Ketones Negative Small, moderate, large Glucose Negative 100, 250, 500, 1000, >1000 mg/dL Protein Negative 30, 100, 300, >2000 mg/dL pH 4.5 - 8.0 Number Leukocyte esterase Negative PositiveMicroscopic ExamA microscopic exam is performed if blood, protein, or leukocyte esterase results are abnormal or if amicroscopic exam is specifically requested. The urine is centrifuged and examined microscopically forWBC, RBC, crystals, casts, bacteria and yeast. Both dipstick and microscopic exam should be performedfor patient populations with a high incidence of genitourinary tract disease.Microscopic urinalysis cannot be completely eliminated because multiple clinically significant findings canonly be detected by examining urine sediment directly. For example, a positive dipstick reaction forblood does not distinguish between red cells, hemoglobin, or casts. Likewise, a positive leukocyteesterase reaction does not distinguish between free WBCs that occur in cystitis, from WBC casts that arecharacteristic of pyelonephritis. Microscopy can detect several other clinically significant abnormalitiesthat are not detected by dipsticks including renal tubular epithelial cells and casts, fatty casts, oval fatbodies, crystalline casts, and crystals.Microscopic examination is considered normal if all of the following criteria are met:  0 to 6 erythrocytes per high power field  0 to 6 leukocytes per high power field  < 3 hyaline or < 1 granular cast per low power field  Absence of any other casts  Absence of significant crystals (i.e. cystine, leucine, tyrosine)Specimen RequirementSpecimen requirement is 10 mL from a random urine collection. A first morning void (overnight)specimen is preferred because it is more concentrated and can be assumed to have been in the bladderfor a number of hours. A dilute specimen is more likely to yield a false negative result.Urine should be tested as soon as possible after collection. Some determinations such as urobilinogen,bilirubin and pH are only valid if obtained on a fresh specimen. Other chemistry results will begin tochange within 2 hours at room temperature. Bacterial growth, cellular degradation, precipitation ofamorphous material, and increasing pH due to urease producing bacteria adversely affect proteinmeasurements. A urine more than 24 hours old, even if refrigerated should not be tested. If urine hasbeen refrigerated, it should be allowed to return to room temperature before testing. Refrigeration maycause an increase in specific gravity and precipitation of amorphous phosphates and urates. Glucosesensitivity is adversely affected by not testing at room temperature. Urinary Tract Infection GuidelinesRoutine urine cultures in uncomplicated cystitis have been shown to increase the cost of care by 39%,but decrease duration of symptoms by only 10%. Recently, guidelines have been published concerningthe use of cultures in evaluating female urinary tract infections. In general, young, sexually active,nonpregnant, immunocompetent females without known GU tract abnormalities presenting with recent-onset dysuria, frequency, or urgency and pyuria meet the definition of uncomplicated cystitis. In thissituation, dipstick testing or urine microscopy should be done to establish the presence of pyuria, butpretreatment urine culture is not required. In this setting, the sensitivity of the dipstick leukocyteesterase is 75-96%. A negative dipstick result should be followed by microscopic exam for pyuria. Othercauses of acute dysuria, including chlamydia, gonorrhea, herpes, and candida or trichomonas vaginitisshould by ruled out by history and urinalysis. Urethritis due to chlamydia, gonorrhea, or herpes usuallyalso results in pyuria, while vaginitis due to Candida or Trichomonas usually does not.
    • While 3 days empiric treatment with Bactrim or a quinolone is suggested for uncomplicated acutecystitis, therapy should be extended to 7 days if symptoms persist more than 7 days, the patient is >65years of age, or there is a history of another recent UTI or diabetes mellitus. In any case, if symptomspersist or relapse occurs within 2 weeks time, urine culture should be done. Pregnant women shouldhave a pre-treatment urine culture and begin empiric therapy with a follow-up urine culture 1-2 weeksafter 7 days of empiric therapy is completed.In summary, in women with typical symptoms, the diagnosis of cystitis can be presumed if pyuria ispresent on leukocyte esterase testing or microscopy. No urine culture is performed and a short course ofempiric antibiotic therapy is given. No follow-up visit or culture after therapy is recommended unlesssymptoms persist or recur. If pyuria is absent or there are atypical clinical features or factors thatsuggest a complicated infection, urine culture should be performed before therapy is started. Urine 24 Hour CollectionMuch confusion exists about the proper way to collect a 24 hour urine specimen. The following protocolis recommended.  24 hour urine specimens should be started Sunday through Thursday.  Instruct the patient to empty their bladder on the morning the collection is to start and to discard this urine.  Collect all urine excreted during the next 24 hours into the urine collection container provided.  If even one urine specimen is missed, the test should be stopped and restarted another morning.  Exactly 24 hours after the collection was begun, the patient should empty their bladder for the last time into the container provided.  The container should be delivered to the laboratory as soon as possible. Urine CultureSince September 1, 1995, urine cultures have been finalized at 24 hours, instead of 48 hours. In arecent study of urine cultures, all uropathogens including yeast were identified by 24 hours incubation.Cultures with growth at greater than 24 hours were contaminants only. This change should result inimproved turn-around-time and fewer contaminant results for the 18,000 urine cultures processedannually. Specimen requirement is 5.0 mL of random urine from a clean, voided midstream urinecollection, catheter, or suprapubic tap in a screw-capped, sterile container. The specimen may berefrigerated up to 24 hours is unable to forward immediately. Reference value is no growth. If growth is>10 colony forming units per mL, bacteria will only be identified. If growth is >100 colony forming unitsper mL, identification and susceptibility testing will be done. Stool Analysis Test OverviewA stool analysis is a series of tests done on a stool (feces) sample to help diagnose certain conditions affecting thedigestive tract , including infection (such as from parasites, viruses, or bacteria), poor nutrient absorption, or cancer.For a stool analysis, a stool sample is collected in a clean container and then sent for laboratory analysis. Laboratoryanalysis includes microscopic examination, chemical tests, and microbiologic tests. A complete stool analysis includesan examination of the physical characteristics of the stool for color, consistency, weight (volume), shape, odor, and thepresence of mucus. The stool may be examined for hidden (occult) blood, fat, meat fibers, bile, white blood cells, andsugars called reducing substances. The pH of the stool also may be measured.A stool culture is done mainly to identify organisms (such as bacteria) that may be causing an infection.Why It Is DoneStool analysis is done to:
    •  Help diagnose diseases of the digestive tract , liver, and pancreas. Certain enzymes (such as trypsin or elastase) may be evaluated in the stool to help determine how well the pancreas is functioning.  Help determine the cause of symptoms affecting the digestive tract, including prolonged diarrhea, bloody diarrhea, an increased amount of gas, nausea, vomiting, loss of appetite, bloating, abdominal pain and cramping, and fever.  Screen for colorectal cancer by checking for hidden (occult) blood.  Detect the presence of parasites, such as pinworms or Giardia lamblia.  Detect and identify certain types of bacteria that can cause disease. This test is called a stool culture and can also be used to detect an infection caused by a fungus or virus.  Detect poor absorption of nutrients by the digestive tract (malabsorption syndrome). For this test, all stool is collected over a 72-hour period and then analyzed for the presence of fat and meat fibers. The presence of fat may indicate a malabsorption problem. This test is called a 72-hour stool collection or quantitative fecal fat test.How To PrepareYou will need to avoid certain medications for 1 to 2 weeks before the sample is collected. These medications includeantacids, antidiarrheal medications, antiparasite medications, antibiotics, enemas, and laxatives.Inform your health professional if you have recently had an X-ray test using barium contrast material, such as a bariumenema or upper gastrointestinal series (barium swallow). Barium can interfere with test results.Also inform your health professional if you have traveled in recent weeks or months, especially if you have traveledoutside your native country. Parasites, fungi, viruses, or bacteria from other countries may affect the test.If your stool is being tested for blood, you will need to follow a special diet for 2 days before the stool collection periodbegins. This diet includes small amounts of chicken, turkey, and tuna (no red meat), raw and cooked vegetables andfruits, bran cereals, peanuts, and popcorn. Avoid turnips, cauliflower, broccoli, bananas, cantaloupe, beets, andparsnips, since these foods can cause inaccurate test results. Do not drink any alcoholic beverages or take aspirin orvitamin C for 2 days before the test.How It Is DoneStool samples can be collected at home, in your health professionals office, at a medical clinic, or at the hospital.You may need to collect samples over a period of time from 1 to 3 days. Follow the same procedure for each day.If you collect the samples at home, you will be given stool collection kits to use each day. Each kit contains applicatorsticks and two sterile containers.Collect the samples as follows:  Urinate before collecting the stool to avoid contaminating the sample.  Put on gloves before handling your stool. Some infectious organisms are contagious while in stool. Wash your hands after you remove your gloves.  Pass stool (but no urine) into a dry container. Your health professional may give you a special container for the test. Do not collect the sample from the toilet bowl. Avoid mixing toilet paper, water, or soap with the sample.  Using one of the applicator sticks, place a small amount of stool in each of the two containers.  Replace the lids and label each with your name, your health professionals name, and the date the stool was collected. Use one kit for each days collection, and collect a sample only once a day unless otherwise directed.Either solid or liquid stool can be collected. Deliver the sealed container within 1 hour to your health professionals officeor directly to a laboratory. Wash your hands well after collecting the sample.If the stool is collected in your health professionals office or the hospital, you will pass the stool in a plastic receptaclethat is inserted under the toilet seat or in a bedpan. Do not urinate while passing the stool. If you have diarrhea, a largeplastic bag taped to the toilet seat may make the collection process easier; the bag is then placed in a plastic container.If you are constipated, you may be given a small enema. The nurse will package the sample for laboratory analysis.If the sample is being tested for quantitative fats, a 72-hour collection period is required. This period starts early in themorning and continues for 3 consecutive days. The stool samples are collected in a large container and refrigerated.
    • If the sample is being collected because you have digestive symptoms after traveling outside your native country,several samples collected over 7 to 10 days may be needed.In infants and young children, samples may be obtained from diapers (if the stool is not contaminated with urine) or froma small-diameter glass tube inserted into the infants rectum while the baby is held on an adults lap.For certain microbiologic tests, the stool sample is collected by a rectal swab. Commercially prepared sterile swabscontaining a preservative are used. The swab is inserted into the rectum past the anal sphincter, without using alubricant, rotated gently, and then withdrawn. It is placed in a clean, dry container and sent for analysis within 60minutes.Pinworm testA stool analysis may be done to detect pinworms. Although this test may be useful, usually it is not the best way todiagnose pinworms since female pinworms do not lay many eggs in the rectum. A simpler method of detectingpinworms can be done using cellophane tape. Press a piece of cellophane tape, sticky side out, to the anal area. Holdthe tape in place for a few seconds. If pinworms are present, they will stick to the tape. The test should be done early inthe morning before bathing or having a bowel movement. The tape test can be done at home or in your healthprofessionals office.How It FeelsCollecting a stool sample normally does not cause any discomfort. If you are constipated, straining to pass stool may bepainful.If your health professional uses a rectal swab to collect the sample, you may feel some pressure or discomfort as theswab is inserted into your rectum.RisksAny stool sample may contain highly infectious organisms that can spread disease. Thorough hand-washing and carefulhandling techniques are essential to avoid spreading a possible infection from the stool sample.ResultsStool analysis test results usually take at least 1 to 3 days. Stool analysisNormal: The stool appears brown, soft, and well-formed in consistency. No blood, mucus, pus, bacteria, viruses, fungi, or parasites are present in the stool. The shape of the stool is tubular, reflecting its passage through the colon. Normal pH of stool is about 6. Less than 2 milligrams per gram (mg/g) of certain sugars called reducing factors are present in the stool.Abnormal: An increased volume of stool may indicate poor absorption of fats. Blood, mucus, pus, bacteria, viruses, fungi, or parasites are present in the stool. Low levels of certain enzymes (such as trypsin or elastase) may be present. pH is less than 5.3 or greater than 6.8. Reducing factors are greater than 5 mg/g; between 2 and 5 mg/g is considered borderline.Abnormal values  High levels of fat in the stool may indicate chronic pancreatitis, sprue (celiac disease), cystic fibrosis, or other disorders that affect the absorption of fats.  The presence of undigested meat fibers in the stool may indicate pancreatitis.
    •  A pH greater than 6.8 may indicate poor absorption of carbohydrates or fat and problems with the amount of bile in the digestive tract. Stool with a pH less than 5.3 may indicate poor absorption of sugars.  Low levels of certain enzymes (such as trypsin or elastase) may indicate digestive complications of the pancreas or problems from conditions, such as cystic fibrosis.  The presence of blood in the stool indicates bleeding in the digestive tract.  The presence of white blood cells in the stool may indicate bacterial diarrhea. A specific organism may be identified.  Rotaviruses are a common cause of diarrhea in young children. If diarrhea is present, testing may be done to determine whether rotaviruses are present in the stool.  High levels of reducing factors in the stool may indicate a problem digesting certain sugars, especially sucrase and lactase. Low levels of reducing factors may occur in sprue (celiac disease), cystic fibrosis, or malnutrition. Medications such as colchicine (for gout) or oral contraceptives may also cause low levels.What Affects the Test  Many medications can interfere with test results, including antibiotics, antidiarrheal medications, barium, bismuth, iron, ascorbic acid, aspirin, and magnesium.  Some foods can affect certain tests. For example, a diet high in red meat can cause false-positive results in testing for hidden (occult) blood.  Stool samples contaminated with urine, menstrual blood, or bleeding hemorrhoids may interfere with results.  Bismuth found in toilet paper and paper towels can interfere with test results.  Exposing the stool sample to air or room temperature or failing to send the sample to a laboratory within 1 hour of collection may make the sample useless for analysis.What To Think About  Stool analysis may be done to check for hidden (occult) blood in the stool. For more information, see the medical test Fecal Occult Blood Test (FOBT).  A stool culture is done mainly to identify bacteria that may be causing an infection. Some viruses also can be identified with a stool culture. Other tests can also be used to detect an infection caused by a fungus or parasite. For more information, see the medical test Stool Culture.  A bowel transit time test may be done by your health professional to help evaluate the cause of abnormal movement of food through the digestive tract. For more information, see the medical test Bowel Transit Time.  The D-xylose absorption test is done to help diagnose problems that prevent the small intestine from absorbing nutrients in food. This test may be done when symptoms of malabsorption syndrome (such as chronic diarrhea, weight loss, and weakness) are present. For more information, see the medical test D- Xylose Absorption Test.  Pancreatic function may be normal in some people with cystic fibrosis. For this reason, a stool analysis to measure trypsin or elastase is not as reliable as the sweat test to detect cystic fibrosis. For more information, see the medical test Sweat Test. Stool Culture Test OverviewA stool culture is done to identify bacteria or viruses that may be causing an infection. More than 50 different kinds ofbacteria normally live in the intestines . However, disease can result if large numbers of abnormal organisms(bacteria, viruses, fungi, or parasites) grow in the intestines. Certain types of viruses, fungi, or parasites can beidentified with a stool culture. A stool culture may be done if you have persistent diarrhea.For a stool culture, a stool sample is collected in a clean container and placed under conditions that allow bacteria orother organisms to grow. The type of infection is identified by noting the appearance of the growth, by performingchemical tests on the stool sample, and by looking at the sample under a microscope. If an infection is found, the test ispositive. If there is no organism growth, the test is negative.Usually several stool samples are collected over a period of days for accurate test results.Why It Is Done
    • A stool culture is done to:  Detect and identify certain types of bacteria, viruses, fungi, or parasites that can cause disease. Symptoms of an intestinal disease may include prolonged diarrhea, bloody diarrhea, an increased amount of gas, nausea, vomiting, loss of appetite, bloating, abdominal pain and cramping, and fever.  Identify a person who may not have any symptoms of disease but who carries bacteria that can spread to others. This person is called a carrier. A person who is a carrier and who handles food is likely to infect others.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How To PrepareNo special preparation is required before having this test. Do not collect a stool sample if you have bleedinghemorrhoids. Women should not collect a stool sample during their menstrual period; wait until 3 days after your periodhas stopped. If you have recently taken antibiotics, traveled out of your native country, or had a recent test with contrastmaterial, tell your health professional when you receive the stool sample collection container.How It Is DoneThe stool sample for this test may be collected at home. If you are in the hospital, a nurse may help you collect thesample.To collect the sample, you need to:  Wear gloves before collecting your specimen.  Pass stool (but not urine) into a dry container. You may be given a container that can be placed under the toilet seat. Either solid or liquid stools can be collected. Avoid mixing toilet paper, water, or soap with the sample.  Seal the container and label it with your name, your health professionals name, and the date the sample was collected.  Wash your hands well after collecting the sample to avoid spreading an infection.  Deliver the sealed container as soon as possible to your health professionals office or directly to the lab.Your health professional may collect a stool sample by gently inserting a cotton swab into your rectum if you are unableto pass a stool sample.How It FeelsCollecting a stool sample does not normally cause any discomfort.If your health professional collects the stool sample during a rectal examination, you may feel some pressure ordiscomfort as the cotton swab is inserted into your rectum.RisksThere are no risks associated with collecting a stool sample. It is important to wear gloves before and wash your handswell after collecting the sample so that you do not spread an infection.ResultsA stool culture is done to identify bacteria, viruses, fungi, or parasites that may be causing an infection. Stool culture testresults usually take 2 to 3 days. Stool cultureNormal: No disease-causing (pathogenic) bacteria, viruses, fungi, or parasites are present or grow in the culture.Abnormal: Pathogenic bacteria (such as salmonella, shigella, campylobacter, certain types of Escherichia coli, or Yersinia enterocolitica) grow in the culture. Some of the more common diseases found using a stool culture include food poisoning and pseudomembranous enterocolitis. Fungi or parasites such as Giardia
    • lamblia are found. Cholera and typhoid fever are less common diseases detected by stool culture.If bacteria are found in the culture, sensitivity testing may be done to determine the best antibiotic to kill the bacteria.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Recent use of antibiotics, medication (such as bismuth) to control diarrhea, enemas, or laxatives.  Recent X-ray tests using a contrast material containing barium.  A stool sample contaminated with urine or blood.  Delay in getting the stool sample to the lab for testing.What To Think About  A stool culture that does not grow any disease-causing (pathogenic) organism may not rule out an infection. Factors such as the amount of stool collected, the type of culture done, and previous use of antibiotics can prevent the growth of an organism in the culture.  Sensitivity testing helps the health professional choose the best medication to kill the specific types of bacteria or fungi infecting a person.  A test for parasites may be done using a sample of stool. Parasites are neither bacteria nor viruses and include organisms such as worms (pinworms, roundworms, tapeworms) and the protozoan Giardia that causes giardiasis. These parasites commonly infect the intestines. The parasites or their eggs can often be seen during an examination of the stool sample under a microscope.  A stool sample can also be checked for the presence of: o White blood cells, which may indicate an infection. If many white blood cells are present but no harmful bacteria grow in the stool culture, other diseases (such as inflammatory bowel disease) may be present. o Blood, which may indicate sores inside the intestines or stomach. o Poisonous substances (toxins) produced by some types of bacteria.  A stool analysis is a series of tests done on a sample of stool to help diagnose certain conditions affecting the digestive tract, including infection, poor absorption, or cancer. For more information, see the medical test Stool Analysis. Stool CulturesRoutine stool cultures for bacterial causes of diarrhea detect Campylobacter, Salmonella and Shigella.Special media to detect E. coli O157 should also be included with all stool cultures because of the seriousnature of this pathogen.Campylobacter is the most common bacterial cause of enteritis worldwide, in both developed &developing nations. Campylobacter enteritis can be associated with significant sequelae includingGuillain-Barre syndrome, and can also result in bacteremia. Campylobacter is a fastidious organism &isolation from stool culture is dependent upon prompt receipt of a fresh specimen in the lab. Non-culturedetection methods for Campylobacter antigen by enzyme immunoassay (EIA) are now available anddetect 25% more Campylobacter isolates than culture alone.E. coli O157 produces shiga toxin and is associated with hemorrhagic colitis and hemolytic uremicsyndrome. Relatively recently, many other serotypes of shiga toxin producing E. coli have beendiscovered that cause similar disease. These serotypes appear to be increasing in prevalence and are notdetected by routine stool cultures. Immunoassays for detection of shiga toxin are available that identifymultiple serotypes and increase detection rates by 20-60%.
    • Fecal Occult Blood Test (FOBT) Test OverviewA fecal occult blood test detects blood in the stool by placing a small sample of stool on a chemically treated card, pad,or wipe; then a chemical developer solution is put on top of the sample. If the card, pad, or cloth turns blue, there isblood in the stool.Fecal occult blood may be done to evaluate some intestinal conditions or to screen for colorectal cancer, which affectsthe large intestine (colon ) and the rectum. In the United States, colorectal cancer is the second leading cause of allcancer deaths. Blood in the stool may be the only symptom of colon cancer. However, not all blood in the stool iscaused by cancer. Other conditions that can cause blood in the stool include:  Hemorrhoids, which are enlarged, swollen veins in the anus. Hemorrhoids can occur inside the anus (internal hemorrhoids) or outside of the anus (external hemorrhoids).  Anal fissures, which are narrow tears that extends from the muscles that control the anus (anal sphincters) up into the anal canal.  Colon polyps: small growths of excess tissue that often grow on a stem or stalk.  Peptic ulcers, which are craterlike sores that develop when the digestive juices produced by the stomach eat away or erode the lining of the digestive tract.  Ulcerative colitis, a type of inflammatory bowel disease (IBD) that causes inflammation and craterlike sores (ulcers) in the inner lining of the colon and rectum.  Gastroesophageal reflux disease (GERD), which is the abnormal backflow (reflux) of food, stomach acid, and other digestive juices into the esophagus.  Crohns disease, which is a form of inflammatory bowel disease that causes inflammation and ulcers that may affect the deepest layers of the lining of the digestive tract.  Use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs).Although fecal occult blood testing may be used to screen for colorectal cancer, it is never used to diagnose thisdisease. Other screening and diagnostic tests for colon cancer include a digital rectal examination, barium enema,flexible sigmoidoscopy, colonoscopy, or CT scan.Checking for hidden (occult) blood in the stool can be done at home. Testing kits are available at pharmacies without aprescription, or your health professional may order a testing kit for you to use at home. If a home fecal occult blood testdetects blood in your stool, contact your health professional.Health ToolsHealth tools help you make wise health decisions or take action to improve your health.Why It Is DoneA fecal occult blood test (FOBT) is done to:  To detect the presence of blood in the stool. Blood in the stool may be caused by hemorrhoids, anal fissure, colon polyps, colorectal cancer, and many other conditions that cause bleeding in the gastrointestinal tract.  To screen for cancer of the colon and rectum (colorectal cancer). FOBT is a useful screening tool for colorectal cancer because cancerous tissue and precancerous polyps are more likely to bleed than normal colon tissue. Polyps and cancers appear to grow slowly and they may not bleed all the time. Sometimes blood in the stool is the only symptom of colon cancer. A FOBT increases the chances that bleeding will be detected. Once detected, additional tests can be done to diagnose the cause of the bleeding. It is important to contact your health professional if a home test detects blood in your stool. Home screening for colon cancer does not replace the need for a regular examination by your health professional.  To help evaluate the possible cause of abdominal pain.  To evaluate the cause of anemia.  As part of a routine physical examination for those at increased risk for colon cancer, especially after the age of 50.How To Prepare
    • Since colon cancers may bleed only intermittently, the test for blood in the stool is done over several days on threedifferent bowel movements. This increases the chance of detecting trace amounts of blood in your stool.To increase the accuracy of the test, you should make some simple diet changes to add roughage to your diet at least 2to 3 days before starting the test and continue until you have collected all three stool samples. Some ways to addroughage to your diet include eating raw and cooked carrots, corn, or spinach; prunes; bran cereals; peanuts; andpopcorn.Before doing a fecal occult blood test (FOBT), avoid the following for 2 to 3 days before the test.  Turnips, beets, radishes, horseradish, artichokes, mushrooms, broccoli, bean sprouts, cauliflower, apples, oranges, bananas, grapes, and melon, since these foods can cause the results to be positive for blood when blood is not in the stool (false-positive test results)  Red meat, because blood in the meat may cause false test results. Small amounts of chicken, turkey, or fish will not interfere with test results.  Iron supplements  Aspirin (or products that contain aspirin) and nonsteroidal anti-inflammatory drugs (NSAIDs)  Vitamin C supplements  Medications, such as colchicine, iodine, antacids, or boric acidDo not perform the test during your menstrual period or if you have active bleeding caused by hemorrhoids. Also, do nottest a stool sample that has been in contact with toilet bowl cleaning products that turn the water blue.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneThe procedure for testing blood in the stool varies depending upon the type of home test you have. It is important tofollow the manufacturers instructions provided with any test. For most tests, you will use stool samples from threedifferent bowel movements over three different days.General instructionsFor any home diagnostic test, follow these general guidelines:  Check the expiration date on the package. Do not use a test kit after its expiration date. The chemicals in the kit may not work properly after that date.  Store the test kit as directed. Many kits need to be stored in a refrigerator or cool place.  Read the instructions that come with your test carefully and thoroughly before doing the test. Pay attention to any special preparations you need to take before doing the test, such as avoiding certain foods or limiting your physical activity.  Follow the directions exactly. Do all the steps, in order, without skipping any of them.  If a step in the test needs to be timed, use a watch. Do not guess at the timing.  If you are color-blind or have trouble distinguishing colors, have someone else read the test results for you. Most test results depend on being able to see color changes on a test strip.  Record the results of the test so you can discuss them with your health professional.The following directions are for one of the most common tests used to detect blood in the stool.Stool guaiac cards  Complete the identification information on the front of each card.  During a bowel movement, collect a small amount of stool on one end of an applicator. You might try catching the stool on some plastic wrap draped loosely over the toilet bowl and held in place by the toilet seat. If you use a container to collect the stool, first clean and rinse it well to get rid of any substance that may affect the test results.  Apply a thin smear of stool inside box A.  Reuse the same applicator to obtain a second sample from a different part of the stool. Apply a thin smear inside box B.  Close the cover of the slide.  Complete the remaining two cards in the same way during two other bowel movements.
    •  You probably will be instructed to return all slides to your health professional either in person or by mail within 4 days of collecting the samples.  If you have the developer solution, wait 3 to 5 minutes before you apply 1 drop of the developer solution to the area containing stool. Apply 1 drop of the developer solution to the control areas of the card so that you will know what positive and negative test results should look like. An area to read the results is found on the reverse side of the card. Turn the card over and read the results within 10 seconds.Other test kits  A kit that uses a special cloth to wipe after a bowel movement can also be used. After wiping with the cloth, the developer solution is put on the cloth to check for color change that indicates blood in the stool.  A special test pad placed in the toilet will change color when a stool with blood interacts with the pad.If you find blood in your stool, contact your health professional as soon as possible.How It FeelsYou may find it unpleasant to collect a stool sample for a fecal occult blood test (FOBT).RisksThere are no risks associated with doing a fecal occult blood test (FOBT).ResultsA fecal occult blood test (FOBT) detects blood in the stool by placing a small sample of stool on a chemically treatedcard, pad, or wipe; then a chemical developer solution is put on top of the sample. If the card, pad, or wipe turns blue,there is blood in the stool. The way results are displayed may vary depending on the type of test you are using. If youare given stool guaiac cards by your health professional, you may not be able read the results yourself. Instead, you willreturn the cards to your health professional, who will then develop them. Fecal occult blood testing Normal: A normal test (no color change) indicates that at the time you collected your stool samples there was no detectable blood in your stool. Normal test results are called negative. Abnormal: An abnormal test (blue color change) may indicate that at the time of the test there was detectable blood in the stool. Abnormal test results are called positive.Normal resultsA negative test result does not rule out the possibility of colon cancer or colon polyps. FOBT is positive in only 30% to50% of the people who have colon cancer. Discuss with your health professional how often you should have an FOBTdepending on your age and any risk factors you may have for colon cancer.Abnormal resultsIf you have a positive test result, it may be caused by something other than colon polyps or colon cancer.  Blood in your stool may be caused by red meat you have eaten, menstrual bleeding, hemorrhoids, Crohns disease, ulcerative colitis, a stomach ulcer, or the use of aspirin or nonsteroidal anti- inflammatory drugs (NSAIDs). If you do not haverisk factors for colon polyps or colon cancer, your health professional may want you to repeat the FOBT. If the repeat test is negative, you may resume regular FOBT screening. If the repeat test is positive, you may have further testing, such as endoscopy, colonoscopy, barium enema, or flexible sigmoidoscopy.  If blood in the stool could be caused by red meat you have eaten, menstrual bleeding, hemorrhoids, Crohns disease, ulcerative colitis, or a stomach ulcer and you have risk factors for colon polyps or colon cancer, your health professional may recommend further testing, such as colonoscopy, barium enema, or flexible sigmoidoscopy, without doing another FOBT.
    • A positive test result may be caused by a polyp, a precancerous polyp, or cancer. With a positive result, there is about a5% to 10% probability that you have early-stage colon cancer. About 50% of the time there is no abnormality found thatcan explain the positive FOBT result.If you have a positive test result and you:  Are younger than 50, and you do not have risk factors for colon polyps or colon cancer, your health professional may want you to repeat the FOBT. If the repeat test is negative, you may resume regular FOBT screening. If the repeat test is positive, you may need further testing, such as colonoscopy, barium enema, or flexible sigmoidoscopy.  Are older than 50, and you have not been evaluated recently for colon polyps, colon cancer, Crohns disease, ulcerative colitis, or stomach ulcers, you will probably need further testing, such as upper gastrointestinal endoscopy, colonoscopy, barium enema, or flexible sigmoidoscopy.  Have been evaluated recently for colon polyps, colon cancer, Crohns disease, ulcerative colitis, or stomach ulcers, your health professional may simply have you repeat the FOBT or you may resume regular FOBT screening.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Medications, such as aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), anticoagulants, or corticosteroids.  The use of laxatives, vitamin C, or iron supplements.  Blood in the urine, menstrual bleeding, hemorrhoids, an anal fissure, bleeding gums, nosebleeds, or eating certain vegetables (radishes, turnips or beets) or red meat cooked rare within 2 days before the test, which can cause a false-positive test result.  The use of a product to clean or deodorize the toilet that contaminates the stool sample.What To Think About  A fecal occult blood test (FOBT) is most often used as a screening tool. By itself, an FOBT cannot be used to diagnose colon polyps or colon cancer. If an FOBT detects blood in the stool, you may need additional tests, such as a rectal exam, colonoscopy, barium enema, endoscopy, or flexible sigmoidoscopy. For more information, see the medical tests Digital Rectal Examination (DRE), Colonoscopy, Barium Enema, Upper Gastrointestinal Endoscopy, Sigmoidoscopy (Anoscopy, Proctoscopy), and Computed Tomography (CT) Scan.  An FOBT has a high rate of false-positive results. This means that the test may be positive when you do not actually have a polyp or cancer. This can occur either because the blood is coming from another source, such as from hemorrhoids, or because the test falsely detected blood. Further testing, such as a colonoscopy, may be done to determine the cause of the positive FOBT results and to rule out serious disease, such as cancer.  People ages 50 to 80 who have an FOBT every 1 to 2 years are up to 33% less likely to die of colorectal cancer than people who do not have regular FOBTs.  Medical experts disagree about routine screening for colorectal cancer. Talk to your health professional about your risk factors and which testing is best for you.Credits Author Jan Nissl, RN, BS Editor Susan Van Houten, RN, BSN, MBA Associate Editor Tracy Landauer
    • Fecal Occult Blood Test (FOBT) Colorectal cancer is the only major cancer that affects men and women almost equally. It is rare inpersons under age 40, but the incidence begins to rise substantially after age 50. About 6% of peopledevelop colorectal cancer by 80 years of age and 50% die as a result of the cancer. Three recentrandomized, controlled trials have convincingly shown that the mortality rate can be reduced 15 to 35%by screening with fecal occult blood tests (FOBT). As a result of these studies, major professionalorganizations such as the American Cancer Society, the United States Preventative Service Task Force,the American College of Physicians, and the College of American Pathologists now recommend annualtesting of all adults at 50 years of age or older. FOBT was also added to the list of approved MedicarePreventive Service Benefits on January 1, 1998.Current guidelines recommend screening with a guaiac-based test such as Hemoccult II, which has beenclassified as a waived test by CLIA 88. Guaiac based FOBT make use of the pseudoperoxidase activity ofhemoglobin. Guaiac turns blue after oxidation by oxidants or peroxidases in the presence of an oxygendonor such as hydrogen peroxide. The likelihood that a guaiac-based test will be positive is proportionalto the quantity of fecal heme, which in turn is related to the size and location of the bleeding lesion.FOBT are optimally designed to detect large, distal lesions. Generally, 10 mL of daily blood loss isrequired for Hemocult II tests to be positive 50% of the time.Patients should collect a total of six samples in order to compensate for sampling error since blood is notevenly distributed in stool. Two slides should be prepared from each of three consecutive bowelmovements. The collection should be made 24 to 48 hours after eating a meat free diet and avoidanceof vitamin C, aspirin, and nonsteroidal anti-inflammatory drugs. Slides need to be developed within 7days of collection. Longer periods of storage cause weakly positive stools to become falsely negative.The dried stool specimens should not be rehydrated with a drop of water at the time of developmentbecause this practice increases the false positive rate up to 16%. A false positive rate of this magnitudeleads to too many nonproductive colonoscopic examinations and makes screening impractical.FOBT is considered positive if even one of the six slide windows turns blue. A middle-aged adult with apositive result on an initial FOBT (performed without slide rehydration) has a 7 to 14% probability ofearly colorectal cancer (Dukes stage A or B). The probability of early cancer or a large (>1 cm) adenomais approximately 30%. Cancer detection rates are lower following rescreening. Nonetheless, cancerdetection rates are high enough to warrant a complete evaluation of the colon and rectum whenever aperson has a positive test either initially or at rescreening. If the results of colonoscopy are negative,FOBT does not need to be repeated for 5 years. If colonoscopy reveals cancer or a high-risk adenoma,periodic colonoscopic surveillance is indicated.A negative result on FOBT does not rule out colorectal cancer, because the sensitivity of the test is only30 to 50%. FOBT should be repeated either annually or biennially. If symptoms develop that suggestcolorectal cancer a more definitive test should be performed to rule out a neoplasm.Antacids and anti-diarrheal medications containing bismuth render the stool dark and may confound thereading of FOBT. Oral iron supplements give the stool a dark-green or black appearance that may beconfused with the blue color of a positive guaiac test.
    • Diabetes Mellitus ManagementDiabetes mellitus is a chronic illness that requires continuing medical care and education to preventacute complications and reduce the risk of chronic complications such as retinopathy, nephropathy, andneuropathy. The Diabetes Control and Complications Trial (DCCT) demonstrated that in patients withtype 1 diabetes the risk of developing these complications was reduced 50 to 75% by intensivetreatment regimens that decreased the average hemoglobin A1c level to 7.2%. The reduction in risk ofthese complications correlated continuously with the reduction in hemoglobin A1c levels, implying thatcomplete normalization of glycemia levels may prevent complications.In view of the DCCTs findings, the American Diabetes Association has recommended the following goalsfor glycemic control in patients with type 1 diabetes. Similar goals have been recommended for patientswith type 2 diabetes. The targets should be adjusted in patients with a history of hypoglycemia. Biochemical Index Nondiabetic Diabetic Goal Action suggested Preprandial glucose <115 mg/dL 80 - 120 mg/dL <80 or >140 Bedtime glucose <120 mg/dL 100 - 140 mg/dL <100 or >160 Hemoglobin A1c <6% <7% >8%Initial Patient VisitDuring the initial visit, laboratory tests should be performed to establish the diagnosis of diabetesmellitus, determine the degree of past and present glycemic control, and determine the presence orabsence of chronic complications and risk factors. Recommended tests include:  Fasting plasma glucose ( random plasma glucose may be obtained in an undiagnosed symptomatic patient for diagnosis)  Glycated hemoglobin  Fasting lipid profile including cholesterol, HDL cholesterol, LDL cholesterol, & triglycerides in adults and children older than 2 years  Serum creatinine in adults and children with proteinuria  Urinalysis including glucose, ketones, protein, and sediment  Urine culture if the sediment is abnormal or patient is symptomatic  Urine microalbumin for postpubertal patients with diabetes for at least 5 years and all patients with type 2 diabetes (timed specimen or albumin/creatinine ratio)  Thyroid function tests when clinically indicatedPatients should be instructed in self monitoring of blood glucose and urine ketones and the use of arecord system. The frequency of blood glucose monitoring should be individualized according to theseverity of illness, treatment plan, and response to treatment.Continuing CarePeriodic follow-up tests play an essential part in the continuing management of every patient withdiabetes. Recommended tests and the suggested frequency of testing are summarized in the followingtable. Laboratory Patient Population Frequency of Testing Test HbA1c Stable glycemic control At least 1 to 2 times per year Poor control or changed therapy Quarterly Lipid profile Initial profile abnormal Annually Treatment for dyslipidemia As needed to monitor therapy
    • Children with normal lipid values Every 5 years Urinalysis Adults Annually Microalbumin Type 1 diabetes beginning at puberty & Annually after 5 years duration Type 2 diabetes at time of diagnosis Annually Creatinine Patients with albuminuria or proteinuria As needed to monitor nephropathy clearance Serum Hypertensive patients treated with ACE As needed to monitor for potassium inhibitors hyperkalemiaGlycated hemoglobin should be performed routinely in all patients with diabetes; first to document thedegree of glycemic control at initial assessment and then as part of continuing care. Since glycatedhemoglobin reflects the mean blood glucose level over the preceding two to three months, repeatmeasurements approximately every three months are required to determine whether a patientsmetabolic control has remained continuously within the target range. Patients with stable glycemiccontrol may require less frequent testing. Glycated hemoglobin levels performed in different laboratoriesshould not be compared or trended.Adult patients with diabetes should be tested for lipid disorders annually with a fasting cholesterol, HDLcholesterol, calculated LDL cholesterol, and triglycerides. If all values are within normal limits, lessfrequent testing may be necessary. Acceptable, borderline, and high risk lipid levels for adults are listedin the following table. Risk for Adult Cholesterol HDL LDL Triglycerides (mg/dL) Diabetics (mg/dL) (mg/dL) (mg/dL) Acceptable <200 <130 <200 Borderline 200 - 239 130-159 200 - 399 High >239 <36 >159 >399Borderline or abnormal values should be repeated for confirmation. Lipid values should be reevaluated inthe presence of a macrovascular event. A lipid profile should be performed on children older than twoyears after glucose control has been established. Borderline or abnormal results should be repeated forconfirmation. If values fall within accepted risk levels, assessment should be repeated every five years.Routine urinalysis should be performed yearly in adults. If positive for protein, quantitation is helpful inmonitoring treatment. If urinalysis is negative for protein, a test for microalbumin is necessary.Microalbumin testing of patients with type 1 diabetes should begin at puberty and after five yearsduration. Patients with type 2 diabetes should be tested at the time of diagnosis. First void or othermorning urine collections are preferred because of the diurnal variation in albumin excretion. Threedifferent microalbumin tests are available:  Measurement of albumin/creatinine ratio on a random, spot collection  24 hour collection with creatinine  Timed collection (e.g. 10 hour)Random urine specimens are often most convenient for outpatients and are generally accurate. There ismarked day to day variability in albumin excretion; therefore, at least two of three microalbumin levelsshould be elevated during a three to six month period before a patient is considered to havemicroalbuminuria. Renal function should be monitored with periodic measurements of creatinineclearance. Hypertensive diabetic patients who are treated with ACE inhibitors should be monitored forhyperkalemia.
    • Diabetes Mellitus, Recommendations for DiagnosisThe Expert Committee on the Diagnosis and Classification of Diabetes Mellitus published newclassification and diagnostic criteria for diabetes in July (Diabetes Care 1997; 20:1183-97). TheCommittee recommended replacing the old categories of insulin dependent diabetes mellitus (IDDM) andnon-insulin dependent diabetes mellitus (NIDDM) with type 1 and type 2 diabetes, respectively.Approximately 700,000 Americans have type1 diabetes, which is caused by autoimmune destruction ofthe pancreatic islet beta cells leading to an absolute deficiency of insulin secretion. It usually occurs inslender children or young adults who are prone to ketoacidosis. Approximately 15.3 million Americanshave type 2 diabetes, which usually arises from a combination of resistance to insulin action and aninadequate compensatory insulin secretory response. Type 2 diabetes usually occurs in adults over 45years who are overweight, sedentary and have a positive family history.The diagnostic criteria for diabetes mellitus have been modified from those previously recommended bythe National Diabetes Data Group (NDDG) and the World Health Organization (WHO). The ExpertCommittee stated that diabetes can be diagnosed in any one of the following three ways:  A fasting plasma glucose of 126 mg/dL or greater (no caloric intake for 8 h);  A casual plasma glucose of 200 mg/dL plus symptoms of diabetes such as polyuria, polydipsia, and unexplained weight loss;  An oral glucose tolerance test (OGTT) value of >/=200 mg/dL in the two hour sample (75 g glucose load).Fasting plasma glucose is the preferred diagnostic test because it is easier to obtain and less subject today to day variation than is the OGTT.The Expert Committee also recommended that testing for diabetes be considered in all adults age 45and older. If results are normal, testing should be repeated at three year intervals. An abnormal resultshould be confirmed on a different day by any one of the three tests. Physicians should consider testingpeople at a younger age who are at risk of diabetes, including those who:  are obese  have a first degree relative with diabetes  are a member of a high risk ethnic group  have a history of gestational diabetes or delivered a baby weighing >9 lb  have hypertension (>=140/90)  have HDL cholesterol < /=35 mg/dL and/or triglyceride level >/=250 mg/dL  have a history of impaired fasting glucose or impaired glucose toleranceThe American Diabetes Association published new recommendations for diabetes screening in January2004 (Diabetes Care 2004;27, Suppl 1:S11-14). Normoglycemia is now defined as a fasting plasmaglucose level of less than 100 mg/dL. Fasting is defined as no consumption of food or beverage otherthan water for at least 8 hours before testing. Nondiabetic individuals with a fasting plasma glucose levelof >100 but < 126 mg/dL are considered to have impaired fasting glucose.Gestational diabetes mellitus (GDM) complicates about 4% of all pregnancies in the United States.Previous recommendations have been that all pregnant women should be screened for GDM with a 50 gOGTT. The Expert Committee now recommends that women at low risk not be screened. This includeswomen who satisfy all of the following criteria: less than 25 years of age, normal body weight, no familyhistory of diabetes, and not a member of an ethnic/racial group with a high prevalence of diabetes (e.g.Hispanic, Native American, Asian, African-American).The revised criteria are for diagnosis of diabetes mellitus and are not treatment criteria or goals oftherapy. No change was made in the American Diabetes Associations recommended treatment goals ofa fasting plasma glucose < 120 mg/dL and HbA1c < 7%.
    • Blood Glucose Test OverviewA blood glucose test measures the amount of a type of sugar, called glucose, in your blood. Glucose comes fromcarbohydrate foods. It is the main source of energy used by the body. Insulin is a hormone that helps your body use andcontrol the amount of glucose in your blood. Insulin is produced in the pancreas and released into the blood when theamount of glucose in the blood rises.Normally, your blood glucose levels increase slightly after you eat. This increase causes your pancreas to releaseinsulin so that your blood glucose levels do not get too high. Blood glucose levels that remain high over time candamage your eyes, kidneys, nerves, and blood vessels.Several different types of blood glucose tests are used.  Fasting blood sugar (FBS) measures blood glucose after you have not eaten for at least 8 hours. It often is the first test done to check for diabetes.  2-hour postprandial blood sugar (2-hour PC) measures blood glucose exactly 2 hours after you eat a meal.  Random blood sugar (RBS) measures blood glucose regardless of when you last ate. Several random measurements may be taken throughout the day. Random testing is useful because glucose levels in healthy people do not vary widely throughout the day. Blood glucose levels that vary widely may indicate a problem. This test is also called a casual blood glucose test.  Oral glucose tolerance test is used to diagnose diabetes that occurs during pregnancy (gestational diabetes). An oral glucose tolerance test is a series of blood glucose measurements taken after you drink a sweet liquid that contains glucose. This test is not recommended for diagnosing diabetes in a person who is not pregnant. For more information, see the medical test Gestational Diabetes.Why It Is DoneBlood glucose tests are done to:  Check for diabetes.  Monitor treatment of diabetes.  Check for diabetes that occurs during pregnancy (gestational diabetes).  Determine if an abnormally low blood sugar level (hypoglycemia) is present. A test to measure blood levels of a protein called C-peptide may be done along with a blood glucose test to determine the cause of hypoglycemia. For more information, see the medical test C-Peptide.How To PrepareFasting blood sugar (FBS)For a fasting blood sugar test, do not eat or drink anything other than water for at least 8 hours before the blood sampleis taken.If you have diabetes, you may be asked to wait until you have had your blood tested before taking your morning dose ofinsulin or diabetes medication.2-hour postprandial blood sugar (2-hour PC)For a 2-hour postprandial test, eat a meal exactly 2 hours before the blood sample is taken. A home blood sugar test isthe most common way to check 2-hour postprandial blood sugar levels.Random blood sugar (RBS)No special preparation is required before having a random blood sugar test.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results may indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is Done
    • The health professional taking a sample of your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsThe blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight.You may feel nothing at all from the needle, or you may feel a quick sting or pinch.RisksThere is very little risk of a problem from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin) and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsNormalA blood glucose test measures the amount of a type of sugar, called glucose, in your blood.Results are usually available within 1 to 2 hours. Blood glucose Fasting blood glucose: 70–99 milligrams per deciliter or less than 5.5 mmol/L 2 hours after eating (postprandial): 70–145 mg/dL (less than 7.9 mmol/L) Random (casual): 70–125 mg/dL (less than 7.0 mmol/L)Normal results may vary from lab to lab. Many conditions can change your blood glucose levels. Your healthprofessional will discuss any significant abnormal results with you in relation to your symptoms and medical history.High values  The American Diabetes Association (ADA) criteria for diagnosing diabetes are met when any of the following results have been repeated on at least two different days: o A fasting blood glucose level is 126 mg/dL (7.0 mmol/L) or higher. o A 2-hour oral glucose tolerance test result is 200 mg/dL (11.1 mmol/L) or higher. For more information, see the medical test Oral Glucose Tolerance Test. o Symptoms of diabetes are present and a random blood glucose test is 200 mg/dL (11.1 mmol/L) or higher. Symptoms of diabetes include increased thirst and frequent urination (especially at night), unexplained increase in appetite, unexplained weight loss, fatigue, erection problems, blurred vision, and tingling or numbness in the hands or feet.  If your fasting blood glucose level is between 100 mg/dL (5.5 mmol/L) and 126 mg/dL (7.0 mmol/L), you are considered to have prediabetes (impaired fasting glucose), and you have an increased chance of getting diabetes.
    •  Other conditions that can cause high blood glucose levels include severe stress, heart attack, stroke, Cushings syndrome, medications such as corticosteroids, cancers, or excess production of growth hormone (acromegaly).Low valuesA fasting glucose level below 40 mg/dL (2.2 mmol/L) in women or below 50 mg/dL (2.8 mmol/L) in men that isaccompanied by symptoms of hypoglycemia may mean you have an insulinoma, a tumor that produces abnormally highamounts of insulin.Low glucose levels also may be caused by:  Addisons disease.  Decreased thyroid hormone levels (hypothyroidism).  A tumor in the pituitary gland.  Liver disease, such as cirrhosis.  Kidney failure.  Malnutrition or an eating disorder, such as anorexia.  Medications used to treat diabetes.What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  Eating or drinking less than 8 hours before a fasting blood test or less than 2 hours before a 2-hour postprandial test.  Drinking alcohol.  Illness or emotional stress, smoking, and caffeine.Taking a medication, such as birth control pills, medications used to treat high blood pressure, phenytoin (Dilantin),furosemide (Lasix), triamterene (Dyrenium, Dyazide), hydrochlorothiazide (Esidrix, Hydro Par, Oretic), niacin,propranolol (Inderal), or corticosteroids (prednisone) can cause changes in your test results. Make sure that your doctorknows about any medicines you take and how often you take them.What To Think About  Other tests are needed to accurately diagnose diabetes. A blood glucose test may not identify some people with prediabetes or early diabetes. Many experts recommend using a glucose tolerance test if the result of a fasting blood glucose test is between 100 mg/dL (5.5 mmol/L) and 126 mg/dL (7.0 mmol/L). This range is above the normal range but below the range that indicates diabetes. For more information, see the medical test Oral Glucose Tolerance Test.  Glucose levels in urine also can be measured. Many people with diabetes have glucose in their urine. However, the level in the blood must be very high before glucose can be detected in the urine. For this reason, tests for glucose in urine are not used to diagnose or monitor diabetes. For more information, see the medical test Urine Test.  If you have diabetes, you will be able to measure your blood glucose levels at home. For more information, see the medical test Home Blood Glucose Test.  A glycohemoglobin test can help monitor the long-term control of blood glucose levels in people with diabetes. This test is the preferred method of monitoring long-term control of blood sugar levels. For more information, see the medical test Glycohemoglobin (GHb).  An oral glucose tolerance test may be done with a blood glucose test to confirm a diagnosis of diabetes. An oral glucose tolerance test is most commonly done to screen pregnant women for gestational diabetes. For more information, see the medical test Oral Glucose Tolerance Test.ReferencesOther Works Consulted  Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.  Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.  Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.
    •  Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby. Glucose, Plasma The American Diabetes Association published new recommendations for diabetes screening in January 2004 (Diabetes Care 2004;27, Suppl 1:S11-14). Fasting plasma glucose levels should be interpreted as summarized in the following table. Fasting Plasma Interpretation Glucose Level <100 mg/dL Normal fasting glucose 100 to 125 mg/dL Impaired fasting glucose >125 mg/dL Provisional diagnosis of diabetes mellitusPatients with impaired fasting glucose are now referred to as having "pre-diabetes" indicating a relatively highrisk for development of diabetes mellitus. Impaired fasting glucose is associated with the metabolic syndrome.Medical therapy aimed at producing 5-10% loss of body weight, exercise and some pharmacologic agents mayprevent or delay development of diabetes in these patients. Individuals with impaired fasting glucose mayhave normal or near-normal HbA1c levels. They often manifest hyperglycemia only when challenged with theoral glucose load used in the oral glucose tolerance test.Fasting is defined as no consumption of food or beverage other than water for at least 8 hours before testing.Specimen requirement is one grey top (potassium oxalate, sodium fluoride) tube of blood.For more information, see Diabetes Mellitus, Recommendations for Diagnosis.
    • Hemoglobin A1cHbA1c refers to a minor population of HbA that has been modified by attachment of glucose to theterminal amino acid of the beta globin chain. The rate of formation of HbA1c is directly proportional tothe plasma glucose concentration. Since erythrocytes are freely permeable to glucose, HbA1c levelsprovide a glycemic history during the average erythrocyte lifespan, which is approximately 120 days.There is broad consensus that HbA1c levels should be used for routine care of all patients with diabetesmellitus. HbA1c levels can be used not only to assess long-term glycemia, but also to predict risk ofdeveloping chronic complications. Baseline HbA1c levels are strongly related to the incidence and/orprogression of retinopathy, gross proteinuria, and loss of tactile sensation or temperature sensitivity.The Diabetes Control and Complications Trial (DCCT), which was completed in 1993, demonstrated thatthe risks for development and progression of the chronic complications of type 1 diabetes are closelyrelated to the degree of glycemic control, as measured by serial glycohemoglobin determinations. TheU.K. Prospective Diabetes Study (UKPDS), which was completed in 1998, showed similar results inpatients with type 2 diabetes. Based on these studies, the American Diabetes Association (ADA) nowrecommends the following goals for glycemic control in patients with IDDM and NIDDM. [Diabetes Care1996; 19 (suppl 1): S8-14]).American Diabetes Association Goals ADA Goals HbA1c Level (%) Nondiabetic <6 Diabetic goal <7 Action suggested >8Optimal frequency of HbA1c testing has not been well established. Currently, it is recommended thattesting be performed during initial patient assessment and at least quarterly thereafter in patients withinsulin dependent diabetes mellitus (IDDM) and as frequently as necessary to assess achievement ofglycemic goals in non-insulin treated patients. Monthly HbA1c levels have been recommended forpregnant women with diabetes, but little scientific data is available to support this recommendation.The laboratory frequently receives questions about the relationship between HbA1c and plasma glucoselevels. HbA1c is a weighted average of blood glucose levels during the preceding 4 months, which is theaverage life span of red blood cells. A large change in mean blood glucose can increase HbA1c levelswithin 1-2 weeks. Sudden changes in HbA1c occur because recent changes in blood glucose levelscontribute relatively more to the final HbA1c levels than earlier events. For instance, mean blood glucoselevels in the 30 days immediately preceding blood sampling contribute 50% to the HbA1c level, whereasglucose levels in the preceding 90-120 day period contribute only 10%. Thus, it does not take 120 daysto detect a clinically meaningful change in HbA1c following a significant change in mean plasma glucoselevel.The Diabetes Control and Complications Trial (DCCT) has published data relating HbA1c to plasmaglucose levels (Diabetes Care 2002; 25:275-78). Mean glucose levels were calculated from 7 pointcapillary glucose measurements made at home before meals, 90 minutes after meals and at bedtime.Glucose meters were calibrated to measure plasma rather than whole blood glucose. The following tablesummarizes the relationship. HbA1c Mean Plasma Glucose (mg/dL) (%) 4 65 5 100 6 135 7 170
    • 8 205 9 240 10 275 11 310 12 345Results showed a linear relationship between HbA1c and mean plasma glucose [MPG = ( 35.6 x HbA1c )- 77] with a Pearson correlation coefficient (r) of 0.82. Each 1% change in HbA1c represents a change ofapproximately 35 mg/dl in plasma glucose. It is important to realize that this data is based on overallaverages and may vary slightly in individual patients.Further analysis of this data demonstrated that among single time point measurements, post-lunch andbedtime plasma glucose levels showed relationships to HbA1c that were most similar to the full 7 pointglucose profile. Fasting glucose levels correlated less well and underestimated HbA1c at higher HbA1cconcentrations. Fasting plasma glucose levels should be used cautiously as a surrogate measure of meanplasma glucose.Understanding the relationship between HbA1c and mean plasma glucose concentration is helpful insetting day to day plasma glucose targets for patients based on the HbA1c goals set by the AmericanDiabetes Association. Unless a patients plasma glucose levels are very stable month after month,quarterly HbA1c measurements are needed to insure that a patients glycemic control remains within thetarget range.Results generated in different laboratories using the same method may differ by as much as 20%, whileresults generated by different methods may vary by 40%. If individual patients have HbA1c resultsperformed in more than one laboratory, the results should not be compared or trended.Results are expressed as the percent of total hemoglobin. Reference range is 4.4 - 6.0%. Specimenrequirement is one lavender top (EDTA) tube of blood.HbA1c for Diagnosis of DiabetesThe clinical use of HbA1c levels has been largely restricted to monitoring diabetic patients. A recentmeta analysis of 18 investigations involving 11,276 patients suggested that HbA1c levels are also usefulin the initial diagnosis of diabetes [JAMA 1996; 276:1246-52]. This study recommended substitutingHbA1c for oral glucose tolerance tests in patients with intermediate fasting plasma glucose levels fallingbetween 115 and 140 mg/dL. The authors stated that HbA1c is more reproducible, informative, andconvenient. In this setting, HbA1c levels of 7% or greater were indicative of diabetes.Hemoglobin A1c as a CV Risk Factor in Nondiabetic IndividualsMacrovascular disease is the most important cause of mortality and morbidity in individuals with type 2diabetes. Even when adjusted for conventional risk factors, diabetic individuals still exhibit a two to fourfold increased risk of cardiovascular disease in comparison to nondiabetic people. Therefore,hyperglycemia is strongly suspected of promoting atherogenesis. Excess glucose is transformed intoadvanced glycation endproducts (AGEs) that not only make blood vessels inelastic and stenotic but alsoactivates chronic inflammation.Hemoglobin A1c concentration is an indicator of average blood glucose concentration over the previousthree months and is the most widely used test to monitor diabetes. Recent studies have demonstratedthat HbA1c is also a predictor of all-cause, cardiovascular and ischemic heart disease mortality even atconcentrations below the accepted threshold for diabetes (British Med J 2001; 322:15-18). The followingtable lists the relative risk of death for each quartile of HbA1c concentration.HbA1c Concentration Mortality <5% 5.0 - 5.5 - 7% 5.4% 6.9% or > All Cause 1.0 1.41 2.07 2.64
    • CV 1.0 2.53 2.46 5.04 Ischemic 1.0 2.74 2.77 5.20Individuals with HbA1c concentrations above 5% had greater risk than individuals with concentrationsbelow 5%. Approximately 25% of population had HbA1c levels below 5% and 70% of the population hadlevels between 5 and 6.9%. HbA1c appears to resemble blood pressure and cholesterol in terms of itscontinuous relationship with cardiovascular risk.Two recent studies in the Annals of Internal Medicine have also validated that HbA1c is a progressiverisk factor for CV disease in individuals with and without diabetes (Ann Intern Med 2004; 141:413-20 &421-31). Every 1% absolute increase in HbA1c above the nonglycemic level of 5% predicts a 20%relative increase in the incidence of CV events even after adjustment for systolic blood pressure,cholesterol level, body mass index, waist to hip ratio, smoking and previous myocardial infarction orstroke. A similar relationship exists for total mortality.
    • Glycohemoglobin (GHb) Test OverviewGlycohemoglobin is a blood test that measures the amount of sugar (glucose) bound to hemoglobin. Normally, only asmall percentage of hemoglobin in the blood (4% to 6%) has glucose bound to it. However, people with diabetes (orother conditions that increase their blood glucose levels) have more glycohemoglobin than normal.Three types of glycohemoglobin—A1a, A1b, A1c—are measured in a total glycohemoglobin test. Test results help monitorthe long-term control of blood glucose levels in people with diabetes. Most health professionals consider theglycohemoglobin A1c level the most effective way to monitor the control of diabetes.Home blood glucose monitoring (self-testing) measures the level of blood glucose only at that moment. However, bloodglucose levels vary throughout the day, depending upon diet, exercise, and the level of insulin in the blood. It is useful toget information about the long-term control of blood sugar levels. The glycohemoglobin test requires only one bloodsample every 3 to 4 months, and the test is not affected by recent changes in diet, exercise, or medications. Glucose isbound to hemoglobin in red blood cells at a steady rate. Since red blood cells last 3 to 4 months, the glycohemoglobinlevel indicates a persons average blood glucose level in the 2 to 3 months before the test.A glycohemoglobin test indicates how well your diabetes has been controlled in the 2 to 3 months before the test.Information gained from a glycohemoglobin test can help determine whether your diabetes medication needs to beadjusted. It can also help your health professional estimate your risk of developing complications from diabetes, such askidney failure, vision problems, and leg or foot numbness.The A1c level is directly related to complications from diabetes: The lower your A1c level, the lower your risk forcomplications.Why It Is DoneThis test is done to monitor treatment for diabetes. It may occasionally be used to help diagnose diabetes.How To PrepareNo special preparation is required before having this test. You do not need to fast before having a glycohemoglobin test.This test can be done any time during the day, even after a meal.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the person drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.
    •  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsGlycohemoglobin is a blood test that measures the amount of sugar (glucose) bound to hemoglobin. The results reflectthe amount of glycohemoglobin divided by the total amount of hemoglobin multiplied by 100 (to produce a percentage).Your A1c level may be reported without a total glycohemoglobin value.NormalNormal values vary from lab to lab, depending on the test method used. Glycohemoglobin (GHb)Glycohemoglobin A1c: 4.5%–5.7%Total glycohemoglobin: 5.3%–7.5% The American Diabetes Association (ADA) recommends that people with diabetes have an A1c level less than 7%. If levels are greater than 8%, the ADA recommends that diabetes treatment be reevaluated.Comparison of hemoglobin A1c and blood glucose levels Hemoglobin A1c Hemoglobin A1c Average blood glucose Average blood glucose levels % (mg/dL) (mmol/L) Severely elevated 10.5 to 14 255 to 360 14.1 to 20 Elevated 8.5 to 10 195 to 240 10.8 to 13.3 Slightly elevated 6.5 to 8 135 to 180 7.5 to 10 Normal 4 to 6 60 to 120 3.3 to 6.7High valuesA glycohemoglobin A1c level above 8% means that your diabetes has been poorly controlled over the previous 2 to 3months.Certain medical conditions can increase A1c levels, but the results may still be within a normal range. These conditionsinclude Cushings syndrome, pheochromocytoma, and polycystic ovary syndrome (PCOS).Corticosteroid treatment increases A1c level.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Severe blood loss or a blood transfusion that occurred within 3 months before the test.  Certain medical conditions, such as sickle cell anemia, hemolytic anemia, and severe kidney disease.  Some types of thalassemia.  Previous removal of the spleen, which affects the normal life cycle of red blood cells and A1c levels.What To Think About  If you have diabetes, your health professional may recommend that you have a glycohemoglobin test every 3 to 6 months, depending on your type of diabetes and how well it is controlled. Generally, A1c is measured 3 to 4 times a year.
    •  The glycohemoglobin test does not replace the need for other regular blood glucose monitoring, including home monitoring and serum glucose testing. For more information, see the medical test Home Blood Glucose Test and Blood Glucose.  Many people with diabetes experience high blood sugars at times they would not routinely do home blood glucose testing, such as after meals or during the night. Glycohemoglobin A 1c may detect these periods of high blood sugar that would not be detected by home blood glucose testing.  Some people who eventually develop diabetes have normal glycohemoglobin test results early in the course of their disease.  Glycohemoglobin levels can be normal in some people who have untreated diabetes and certain medical conditions, such as sickle cell anemia, hemolytic anemia, severe kidney disease, or pregnancy.  The level of glycohemoglobin and the risk of developing complications caused by diabetes are related. The Diabetes Control and Complications Trial (DCCT), a major study sponsored by the National Institutes of Health, showed that lowering the glycohemoglobin in a person with type 1 diabetes can delay or prevent the development of serious nerve, kidney, and eye damage. The United Kingdom Prospective Diabetes Study (UKPDS) showed that better control of blood sugar in people with type 2 diabetes also leads to fewer complications.  Normal glycohemoglobin levels can vary greatly between labs, depending on the testing method used. For this reason, it is important to use the same laboratory when having glycohemoglobin levels repeated. The American Diabetes Association (ADA) recommends that laboratories use testing methods endorsed by the Diabetes Control and Complications Trial (DCCT).  Glycohemoglobin levels are not useful for detecting low blood sugar (hypoglycemia).Sodium (Na) in BloodTest OverviewA sodium test measures the amount of sodium (an electrolyte and a mineral) in the body. Sodium helps regulate thewater balance (the amount of fluid inside and surrounding the cells) and electrolyte balance of the body. Sodium alsoplays an important role in nerve and muscle functions. It carries an electrical charge when it is dissolved in blood.Most of the sodium in the body (about 85%) is found in the fluids that surround the bodys cells (such as blood andlymph fluid). Sodium levels in the body are partially controlled by a hormone called aldosterone, which is produced bythe adrenal glands. Aldosterone causes the kidneys to retain sodium that is normally lost through the urine. (See anillustration of the adrenal glands or the kidneys .) Small amounts of sodium are also lost through the skin insweat.Almost all foods contain sodium naturally or as an ingredient, such as table salt (sodium chloride) or baking soda(sodium bicarbonate) added in processing or while cooking. Many medicines and other products also contain sodium,including laxatives, aspirin, mouthwash, and toothpaste.Too much sodium in the diet may raise blood pressure in some people. For those who already have high bloodpressure, a diet high in sodium may further increase their risk of heart disease, stroke, and kidney damage. Highsodium intake can worsen heart failure and can increase the amount of water retained by the body, leading to swellingof the legs and hands. Taking in more than 4,000 milligrams (mg) of sodium per day causes problems for some people.Low blood sodium levels are uncommon and most often occur as a side effect of taking medications that increaseurination (diuretics). Severe diarrhea or vomiting or heavy sweating may also cause low blood sodium levels.Other electrolytes, such as potassium, calcium, chloride, magnesium, and phosphate, may be measured in a bloodsample at the same time as a blood test for sodium.Why It Is DoneA test to measure sodium levels is done to:  Evaluate the water balance (the amount of fluid inside and surrounding the cells) and electrolyte balance of the body.  Evaluate symptoms that may be caused by abnormal low or high levels of sodium.  Monitor diseases of the kidneys or adrenal glands.How To Prepare
    • No special preparation is required before having this test.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneBlood testThe health professional drawing blood will  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsA sodium test measures the amount of sodium (an electrolyte and mineral) in the body. Normal values may vary fromlab to lab. SodiumBlood: 135–145 millimoles per liter (mmol/L)Urine: 10–40 mmol/L (can range from undetectable to 150 mmol/L)Many conditions can affect sodium levels.Your health professional will discuss any significant abnormal results with youin relation to your symptoms and medical history.High values  High sodium levels (hypernatremia) can be caused by a high-sodium diet or by not drinking enough water (dehydration).  High sodium levels can also result from abnormally high levels of the hormone aldosterone (hyperaldosteronism) or from dehydration caused by severe vomiting or diarrhea, Cushings syndrome,
    • kidney disease or injury, diabetic ketoacidosis, or a condition caused by the inability to regulate levels of water in the body properly (diabetes insipidus).Low values  Low sodium levels (hyponatremia) can be caused by excessive sweating, burns, severe vomiting or diarrhea, drinking too much water (psychogenic polydipsia), or poor nutrition.  Low sodium levels can also be caused by underactive adrenal glands or thyroid gland, heart failure, kidney disease, cirrhosis, cystic fibrosis, or SIADH (syndrome of inappropriate antidiuretic hormone secretion).What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Medications, such as birth control pills, corticosteroids, antibiotics, estrogens, tricyclic antidepressants, heparin, nonsteroidal anti-inflammatory drugs (NSAIDs), diuretics, lithium, and many medications used to treat high blood pressure.  High levels of glucose, triglycerides, or protein.  The amount of sodium in intravenous fluids given during surgery or a hospitalization.What To Think About  A rapidly changing sodium level often causes more symptoms than when the level changes slowly. Symptoms of an abnormal sodium level include confusion, lack of energy (lethargy), or seizures.  It is important to evaluate the bodys water content (too much or too little water) when evaluating a low sodium level.  To determine whether the body is releasing too little or too much sodium in the urine, a value called the fractional excretion of sodium (FENA) is calculated from the amounts of sodium and creatinine in blood and urine. In a person with kidney failure, a low FENA may indicate that reduced blood flow to the kidneys is causing the kidney failure. A urine test for sodium may be done. For more information, see the medical test Sodium in Urine.  Other electrolytes, such as calcium, chloride, magnesium, potassium, phosphate, blood urea nitrogen (BUN), and creatinine, may be measured in a blood sample at the same time as a blood test for sodium. For more information, see the medical tests Calcium in Blood, Chloride (Cl), Magnesium (Mg), Potassium in Blood, Phosphate, Blood Urea Nitrogen, and Creatinine and Creatinine Clearance.
    • Oral Glucose Tolerance Test (OGTT) Test OverviewThe oral glucose tolerance test (OGTT) measures the bodys ability to use a type of sugar, called glucose, that is thebodys main source of energy. An OGTT is most commonly done to check for diabetes that occurs with pregnancy(gestational diabetes).Why It Is DoneThe oral glucose tolerance test (OGTT) is done to:  Check pregnant women for gestational diabetes. When done for this purpose, the test is called a glucose challenge screening test, and it is usually done during the 24th to the 28th week of pregnancy. You have an increased chance of developing gestational diabetes if you: o Have had gestational diabetes during a previous pregnancy. o Have previously given birth to a baby who weighed more than 8.8 lb(4 kg). o Are younger than age 25 and were overweight before getting pregnant.  Confirm the presence of gestational diabetes if other blood glucose measurements are high.  To screen women who have polycystic ovary syndrome (PCOS) for diabetes.How To PrepareGlucose challenge screening test for gestational diabetesNo preparation is usually needed for the screening test done during pregnancy. This test can be done at any time of theday; therefore, you do not need to limit food or fluids before the test.Glucose tolerance diagnostic testTo prepare for the glucose tolerance diagnostic test:  Eat a balanced diet that contains at least 150 to 200 grams of carbohydrate per day for 3 days before the test. Fruits, breads, cereals, grains, rice, crackers, and starchy vegetables such as potatoes, beans, and corn are good sources of carbohydrate.  Do not eat, drink, smoke, or exercise strenuously for at least 8 hours before your first blood sample is taken.  Tell your health professional about all prescription and nonprescription medications you are taking. You may be instructed to stop taking certain medications before the test.The glucose tolerance diagnostic test may take up to 4 hours. Since activity can interfere with test results, you will beasked to sit quietly during the entire test. Do not eat during the test. You may drink only water during this time.Talk to your health professional about any concerns you have regarding the need for the test, its risks, or how it will bedone. To help you understand the importance of this test, fill out the medical test information form (What is a PDFdocument?).How It Is DoneGlucose challenge screening test for gestational diabetes  You will be asked to drink a sweet liquid containing glucose. It is best to drink the liquid quickly.  A blood sample will be collected 1 hour after you drink the glucose. Normally, blood glucose levels peak within an hour and then begin to drop.If the screening test results indicate that you may have gestational diabetes, the complete glucose tolerance diagnostictest may be done.Glucose tolerance diagnostic testOn the day of testing, the following steps will be done:
    •  A blood sample will be collected when you arrive. This is your fasting blood glucose value. It provides a baseline for comparing other glucose values.  You will be asked to drink a sweet liquid containing a measured amount of glucose. It is best to drink the liquid quickly. For the standard glucose tolerance test, you will drink 75 g(3 oz) to 100 g(4 oz); pregnant women drink 100 g(4 oz) of glucose.  Blood samples will be collected at timed intervals of 1, 2, and 3 hours after you drink the glucose. Blood samples may also be taken as soon as 30 minutes to more than 3 hours after you drink the glucose.Glucose challenge screening test for polycystic ovary syndrome (PCOS)  You will be asked to drink a sweet liquid containing glucose. It is best to drink the liquid quickly.  A blood sample will be collected 2 hours hour after you drink the glucose. Normally, blood glucose levels peak within an hour and then begin to drop.If the screening test results indicate that you may have diabetes, other tests may be needed.Blood testThe health professional taking a sample of your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may find it difficult to drink the extremely sweet glucose liquid. Some people feel sick after drinking the glucoseliquid and may vomit. Vomiting may prevent you from completing the test on that day.The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight.You may feel nothing at all from the needle, or you may feel a quick sting or pinch.You may feel faint from having several blood samples taken in one day. However, the amount of blood taken will notcause significant blood loss or anemia.RisksSome peoples blood glucose levels drop very low toward the end of the test. Symptoms of low blood glucose includeweakness, hunger, sweating, and feeling nervous or restless. If this happens, the test will be stopped.There is very little risk of a problem from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin) and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsThe oral glucose tolerance test (OGTT) measures the bodys ability to use a type of sugar, called glucose, that is thebodys main source of energy.Normal
    • Normal plasma glucose values may vary from lab to lab. Glucose challenge screening test (for gestational diabetes) 50 grams (g) of 1- Less than 140 milligrams per deciliter (mg/dL) or 7.8 millimoles per liter (mmol/L) glucose hour: If values are between 140–180 mg/dL (7.8–10.2 mmol/L), a glucose tolerance diagnostic test may be recommended. Glucose tolerance diagnostic test (for gestational diabetes) 100 g of glucose Fasting: 70–115 mg/dL or less than 6.4 mmol/L 1-hour: Less than 200 mg/dL or 11.1 mmol/L 2-hour: Less than 140 mg/dL or 7.8 mmol/L 3-hour: 70–115 mg/dL or less than 6.4 mmol/L Glucose tolerance screening test (for diabetes in women who have polycystic ovary syndrome) 75 g of glucose 2-hour: Less than 140 mg/dL or 7.8 mmol/LHigh valuesHigh glucose levels may be caused by:  Gestational diabetes.  Polycystic ovary syndrome (PCOS).  Medications, such as corticosteroids, niacin, phenytoin (Dilantin), some diuretics, and some medications used to treat high blood pressure.  Severe stress.  Large amounts of the hormone cortisol in the blood (Cushings syndrome).  Inherited diseases, such as cystic fibrosis, pheochromocytoma, or hemochromatosis.  Overproduction of growth hormone (acromegaly).Low valuesLow glucose levels may be caused by:  Medications, such as medications used to treat diabetes, some blood pressure medications (such as propranolol), and some medications for depression (such as isocarboxazid).  A condition that prevents the intestines from absorbing nutrients from food, such as celiac disease.  Decreased production of the hormones cortisol and aldosterone (Addisons disease).  Problems with the thyroid gland (hypothyroidism) or an underactive pituitary gland.  A tumor of the pancreas (insulinoma).  Inflammation and scarring of the liver (cirrhosis).Many conditions can change blood glucose levels. Your health professional will discuss any significant abnormal resultswith you in relation to your symptoms and medical history.What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  Medications, such as corticosteroids, diuretics, seizure medications, birth control pills, nonsteroidal anti- inflammatory drugs (NSAIDs), and some medications used to treat high blood pressure.  Alcohol.  Recent surgery, heart attack, or childbirth.
    •  A low-carbohydrate diet.  Vomiting during the test.  Emotional stress.  Fever and infection.Your health professional will discuss with you any factors that can interfere with your test and the accuracy of theresults.What To Think About  Although an oral glucose tolerance test can indicate the presence of diabetes in people who are not pregnant, the American Diabetes Association and the Canadian Diabetes Association do not recommend using it to diagnose diabetes. If an oral glucose tolerance test is done, a second blood glucose test—preferably a fasting blood glucose—is done before a diagnosis of diabetes can be established. For more information, see the medical test Blood Glucose.  The glucose liquid may be replaced with a carbonated drink that contains glucose, such as soda pop, or a gelatin that contains glucose. These forms of glucose may be easier to drink or eat than a plain glucose solution.  Glucose tolerance test screening by age 30 is recommend for all women who have polycystic ovary syndrome. For more information, see the topic Polycystic Ovary Syndrome (PCOS).ReferencesOther Works Consulted  American Association of Clinical Endocrinologists (2005). Position statement on metabolic and cardiovascular consequences of polycystic ovary syndrome. Endocrine Practice: 11(2): 126–134.  Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.  Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.  Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.  Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.
    • Glucose Meter AccuracyThe introduction of tight glycemic control protocols in hospitals has increased the need for more accuratebedside glucose meters. In 1987, the American Diabetes Association (ADA) recommended that glucosemeters should have a total error (analytic plus user) of < 10% at glucose concentrations between 30 to400 mg/dL. More recently, ADA urged manufacturers to further decrease total error to 5%. Currentlyavailable meters do not meet these performance goals. Recent proficiency testing results from theCollege of American Pathologists demonstrate that glucose meters have much more instrument toinstrument variability than chemistry analyzers in central laboratories. For example, the interlaboratoryprecision at a glucose value of 400 mg/dL ranged from 4.1% to 13.7% for glucose meters compared to1.6% to 2.8% for chemistry analyzers.The laboratory often receives questions concerning the disparity between a glucose result obtained witha glucose meter and a subsequent result performed on a chemistry analyzer in the laboratory. In mostinstances, the glucose meter result has been incorrect. The most common causes of erroneous resultsobtained with glucose meters include:  Under or overfilling of the glucose strip  Contamination or dilution of the sample, especially if drawn from a line  Clotting of the sample due to delayed testing
    • Glucose Tolerance 75 Gram DoseBlood glucose concentrations are tightly regulated through the coordinated actions of insulin andcounter-regulatory hormones, such as glucagon and epinephrine. Diabetes mellitus is characterized byelevated plasma glucose concentrations resulting from insufficient insulin, insulin resistance, or both.Type 1diabetes accounts for less than 10% of all diabetes, while type 2 diabetes accounts for theremaining 90%. Gestational diabetes occurs in 3% of all pregnancies.The American Diabetes Associations criteria for the diagnosis of diabetes mellitus include:  A fasting glucose of 126 mg/dL or greater. Fasting is defined as no caloric intake for at least 8 hours.  A casual plasma glucose of 200 mg/dL or greater plus symptoms of diabetes. Casual is defined as any time of day without regard to time since last meal.  A 2 hour postload value of 200 mg/dL or greater after a 75 g oral glucose tolerance test.Any of these 3 criteria can be used to diagnose diabetes. In the absence of unequivocal hyperglycemia,each must be confirmed on a subsequent day by any one of these methods.The National Diabetes Data Group guidelines for the oral glucose tolerance test are:  The test should be done in the morning after a 10 to16 hour fast, preceded by 3 days of diet containing at least 150 g of carbohydrate, and unrestricted physical activity.  After obtaining a fasting specimen, a 75 g glucose loading dose is consumed over 5 minutes.  The patient should remain seated throughout the test & may drink as much water as desired.  Blood is drawn at 1, 2, & 3 hours after the glucose load.  Specimens should be refrigerated after collection.Specimen requirement is one gray top (potassium oxalate-sodium fluoride) tube of blood drawn beforethe glucose dose and at 1 and 2hours after the glucose challenge.
    • Glucose Tolerance for Gestational DiabetesGestational diabetes is defined as carbohydrate intolerance of varying degrees of severity with onsetduring pregnancy. Rather than predicting the development of diabetes later in life, as originallyproposed, the main purpose of identifying gestational diabetes is to detect women at risk of adverseperinatal outcomes. Gestational diabetes affects ~14% of pregnant women. After a pregnancy withGDM, a woman has an increased risk of developing type 2 diabetes mellitus within 10 years postpartum.Fetal macrosomia affects 40% of the offspring of women with GDM. Macrosomia is associated withincreased risk of birth injuries as a result of the large size of the fetus. Infants of women with GDM areat higher risk of developing obesity, impaired glucose tolerance or diabetes mellitus at an early age.Keeping 1-hour postprandial blood glucose levels between 120 and 140 mg/dL minimizes the risk ofmacrosomia.Recent guidelines do not recommend screening women who are:  Under 25 years of age  Normal body weight  No personal or family history of abnormal glucose metabolism  No history of poor obstetric outcome  Do not belong to an ethnic/racial group with a high prevalence of diabetes (Hispanic American, Asian American, African American, Pacific Islander)Pregnant women who have a a fasting plasma glucose level >126 mg/dL or a casual plasma glucoselevel of >200 mg/dL during their initial prenatal visit meet the threshold for the diagnosis of diabetes. Inthe absence of unequivocal hyperglycemia, the diagnosis must be confirmed on a subsequent day.Confirmation precludes the need for any glucose challenge.In the absence of overt hyperglycemia, the recommended screening test for women at high risk ofgestational diabetes is the 50-gram 1-hour glucose tolerance test. Screening should be performed at 24to 28 weeks gestation, at any time of day, and without regard to previous meals.The test is performed as follows:  The glucose-loading dose of 50 g is consumed over 5 minutes.  The patient should remain seated and can drink as much water as desired.  Blood is drawn at 1 hour after the glucose challenge.  The specimen should be refrigerated after collection.A glucose value >140 mg/dL is considered a positive gestational diabetes screening test. This cutoffvalue identifies 80% of women with gestational diabetes. Sensitivity is increased to 90% if a cutoff of>130 mg/dL is used.ACOG recommends further testing when the 1-hour result is >130 mg/dL. Nearly 25% of women willhave a positive 1-hour test and require evaluation with the 3-hour test.Most of the world uses the criteria of the World Health Organization (WHO) to diagnose GDM, which arebased on a 75-g glucose load. However, physicians in the United States use the criteria endorsed by theNational Diabetes Data Group (NDDG) and the ADA, which are based on a 100-g glucose load. Anabnormal oral glucose tolerance test is defined as two or more blood glucose concentrations as high orhigher than those listed in the following table.
    • Criteria for the Diagnosis of Gestational Diabetes Mellitus NDDG ADA ADA WHO IGT WHO GDM Glucose 100 100 75 75 75 Load FPG 105 95 95 NA 140 1 h pp 190 180 180 180 NA 2 h pp 165 155 155 155 200 3 h pp 145 140 140 NA NAFBG = fasting plasma glucose; pp=postprandialSpecimen requirement is one gray top (potassium oxalate-sodium fluoride) tube of blood.
    • Glucose 6 Phosphate Dehydrogenase Screen (G6PD), Red Blood CellG6PD is an enzyme necessary for the production of NADPH through the pentose phosphate pathway inthe red blood cell. NADPH is required in the red cell to reduce glutathione, which protects hemoglobinfrom oxidative damage. If G6PD is present, NADP will be converted to NADPH, which will fluoresce.G6PD deficient blood will not fluoresce.With G6PD deficiency, hemoglobin is susceptible to oxidant damage, and denatured globin precipitates inthe RBC forming Heinz bodies. This leads to membrane rigidity and premature removal of red cells bythe liver and spleen. G6PD deficiency is a common cause of drug induced hemolytic anemia. Clinicallysignificant hemolysis may occur with numerous drugs including antimalarials, sulfonamides andanalgesics. Hemolysis may also occur with infections or after eating fava beans (favism).Results are reported as normal or deficient. The reference value is normal.Specimen requirement is one lavender top (EDTA) tube of blood.
    • Glucose, Spinal FluidGlucose enters the spinal fluid from the plasma by both diffusion and active transport. The concentrationand duration of plasma glucose influence the spinal fluid level. Typically, spinal fluid glucoseconcentration is 60 to 70% of plasma glucose and lags behind the plasma level by 30 to 90 minutes. Anincrease in spinal fluid glucose means the patient was hyperglycemic 30 to 90 minutes before and is notclinically significant. Spinal fluid glucose may be decreased by bacterial, fungal, and mycobacterialmeningitis; primary and metastatic cancer, subarachnoid hemorrhage; and hypoglycemia. Spinal fluidglucose is decreased in 60 to 80% of bacterial meningitis cases. Viral meningitis and neurosyphilisusually do not affect spinal fluid glucose concentration.Reference range is 40 to 80 mg/dL.Specimen requirement is 1 mL of spinal fluid.
    • Cholesterol and Triglycerides Tests Test Overview Cholesterol and triglyceride tests are blood tests that measure the total amount of fatty substances (cholesterol and triglycerides) in the blood. Cholesterol travels through the blood attached to a protein. This cholesterol-protein package is called a lipoprotein. Lipoprotein analysis (lipoprotein profile or lipid profile) measures blood levels of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides.  Cholesterol. The body uses cholesterol to help build cells and produce hormones. Too much cholesterol in the blood can build up along the inside of the artery walls, forming what is known as plaque. Large amounts of plaque increase your chances of having a heart attack or stroke.  HDL (high-density lipoprotein) cholesterol helps remove fat from the body by binding with it in the bloodstream and carrying it back to the liver for disposal. It is sometimes called ―good‖ cholesterol. A high level of HDL cholesterol may lower your chances of developing heart disease or stroke.  LDL (low-density lipoprotein) cholesterol carries mostly fat and only a small amount of protein from the liver to other parts of the body. It is sometimes called "bad cholesterol." A high LDL cholesterol level may increase your chances of developing heart disease.  VLDL: (very low-density lipoprotein) cholesterol contains very little protein. The main purpose of VLDL is to distribute the triglyceride produced by your liver. A high VLDL cholesterol level can cause the buildup of cholesterol in your arteries and increases your risk of heart disease and stroke.  Triglycerides are a type of fat the body uses to store energy. Only small amounts are found in the blood. Having a high triglyceride level along with a high LDL cholesterol may increase your chances of having heart disease more than having only a high LDL cholesterol level.Some medical experts recommend routine cholesterol and triglyceride testing to screen for problems that affect the waycholesterol is produced, used, carried in the blood, or disposed of by the body. Others may choose to routinely measureonly total cholesterol and HDL levels.  National Cholesterol Education Panel (NCEP) guidelines for cholesterol screening  U.S. Preventive Services Task Force (USPSTF) guidelines for cholesterol screening  American College of Physicians (ACP) guidelines for cholesterol screening  American Academy of Pediatrics guidelines for cholesterol screening in children and teens (ages 2 to 20)  American Heart Association guidelines for preventing coronary artery disease and strokeWhy It Is DoneCholesterol and triglyceride testing is done:  As part of a routine physical exam to screen for a lipid disorder.  To check your response to medicines used to treat lipid disorders.  To help determine your chances of having of heart disease, especially if you have other risk factors for heart disease or symptoms that suggest heart disease is present.  If you have unusual symptoms, such as yellow fatty deposits in the skin (xanthomatosis), which may be caused by a rare genetic disease that causes very high cholesterol levels.How To PreparePreparation depends on the test. Ask your health professional which test you are having.  Do not eat or drink anything except water for 9 to 12 hours before having your blood drawn. Usually, you are allowed to take your medicines with water the morning of the test. Fasting is not always necessary, but it may be recommended.  Do not eat high-fat foods the night before the test.  Do not drink alcohol or exercise strenuously before the test.Many medicines may affect the results of this test. Be sure to tell your health professional about all the nonprescriptionand prescription medicines and herbs or natural substances you take.Tell your health professional if you have had a test such as a thyroid or bone scan that uses a radioactive substancewithin the last 7 days.
    • Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneThe health professional taking a sample of your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Put a gauze pad or cotton ball over the needle site as the needle is removed.  Put pressure on the site and then put on a bandage.How It FeelsThe blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight.You may feel nothing at all from the needle, or you may feel a quick sting or pinch.RisksThere is very little chance of a problem from having blood sample taken from a vein.  You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.  In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.  Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your health professional before your blood sample is taken.ResultsCholesterol and triglyceride tests are blood tests that measure the total amount of fatty substances (cholesterol andtriglycerides) in the blood.Results are usually available within 24 hours.Cholesterol and triglyceride levels vary according to your age and sex. Results may also vary from lab to lab. Cholesterol and triglycerides* Total cholesterol Desirable:  Less than 200 milligrams per deciliter (mg/dL)  Less than 5.17 millimoles per liter (mmol/L) Borderline high:  200–239 mg/dL  5.17–6.18 mmol/L High:  240 mg/dL or higher  6.21 mmol/L or higher HDL cholesterol High (desirable):  More than 60 mg/dL  More than 1.56 mmol/L Acceptable:  40–60 mg/dL
    •  1.04–1.56 mmol/L Low (undesirable):  Less than 40 mg/dL  Less than 1.04 mmol/L Total cholesterol-to-HDL ratio Desirable:  5:1 or less Undesirable:  More than 5:1 LDL cholesterol Optimal:  Less than 100 mg/dL  Less than 2.6 mmol/L Near optimal:  100–129 mg/dL  2.6–3.35 mmol/L Borderline high:  130–159 mg/dL  3.38–4.10 mmol/L High:  160–189 mg/dL  4.12-4.88 mmol/L or higher Very high:  190 mg/dL or higher  4.90 mmol/L or higher VLDL cholesterol Optimal:  Less than 130 mg/dL  Less than 3.4 mmol/L Borderline high:  140–159 mg/dL  3.4–4.1 mmol/L High:  160 mg/dL or higher  4.1 mmol/L or higher Triglycerides Normal:  Less than 150 mg/dL  Less than 1.69 mmol/L Borderline high:  150–199 mg/dL  1.69–2.25 mmol/L High:  200-499 mg/dL  2.26-5.63 mmol/L Very high:  500 mg/dL or higher  5.64 mmol/L or higher*The figures in this table are provided by the National Cholesterol Education Program (NCEP) of the National Institutesof Health (NIH).
    •  An HDL level of 60 mg/dL (1.56 mmol/L) or higher protects against heart disease.  HDL cholesterol levels of 40 mg/dL (1.04 mmol/L) or lower increase your risk of developing heart disease, especially if you also have high total cholesterol levels.  Very high cholesterol and triglyceride levels may be caused by an inherited form of high cholesterol (hypercholesterolemia or hyperlipidemia).Many conditions can affect cholesterol and triglyceride levels. Your health professional will talk with you about anyabnormal results that may be related to your other health problems.What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  Medicines, such as diuretics, corticosteroids, male sex hormones (androgens), tranquilizers, estrogen, birth control pills, antibiotics, and niacin (vitamin B3).  Physical stress, such as infection, heart attack, surgery.  Eating 9 to 12 hours before the test.  Other conditions, such as hypothyroidism, diabetes, or kidney or liver disease.  Alcohol or drug abuse or withdrawal.  Liver disease (such as cirrhosis or hepatitis), malnutrition, or hyperthyroidism.  Pregnancy. Values are the highest during the third trimester and usually return to the prepregnancy levels after delivery of the baby.What To Think About  Having a high cholesterol level increases your chances of having a heart attack. The higher your cholesterol, the greater your chances. An elevated total cholesterol level in younger people is particularly significant, since the narrowing of the coronary arteries usually takes many years to develop.  Lifestyle changes (such as diet changes, weight loss, and exercise) may help lower blood cholesterol levels and increase HDL ("good") cholesterol. Some people have better responses to diet and lifestyle changes than do others. Lifestyle changes might include: o Reducing saturated (animal) fats and cholesterol in the diet while increasing fiber and complex carbohydrates. o Losing weight. An improvement may occur if you lose as little as 5 lb(2.3 kg) to 10 lb(4.5 kg).  Moderate consumption of alcohol can also increase HDL cholesterol. o Moderate alcohol consumption means no more than 2 drinks per day for men or 1 drink per day for women; 1 drink is 12 fl oz(355 mL) of beer, 5 fl oz(148 mL) of wine, or 1.5 fl oz(44 mL) of liquor. o The benefits of alcohol consumption must be balanced against the increased risk of alcoholism, high blood pressure, heart problems such as atrial fibrillation and heart failure, and cirrhosis.  The National Cholesterol Education Program (NCEP) has developed a risk assessment calculator to estimate your risk of having a heart attack or dying from coronary artery disease over 10 years. This tool is designed to estimate risk in adults age 20 and older who do not have heart disease or diabetes. Use the Interactive Tool: Are You at Risk for a Heart Attack? to calculate your risk of coronary artery disease.  Talk to your health professional about which cholesterol screening is best for you. Medical experts disagree about routine screening for lipid disorders. o National Cholesterol Education Panel (NCEP) guidelines for cholesterol screening o U.S. Preventive Services Task Force (USPSTF) guidelines for cholesterol screening o American College of Physicians (ACP) guidelines for cholesterol screening o American Academy of Pediatrics guidelines for cholesterol screening in children and teens (ages 2 to 20) o American Heart Association guidelines for preventing coronary artery disease and stroke  Cholesterol screening is often available in supermarkets, pharmacies, shopping malls, and other public places. Home cholesterol testing kits also are available. The results of tests done outside a doctors office or lab may not be accurate. If you have cholesterol screening done outside your doctors office, talk with your doctor about the accuracy of the results.ReferencesOther Works Consulted  Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.  Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.
    •  Genest J, et al. (2003). Recommendations for the management of dyslipidemia and the prevention of cardiovascular disease: Summary of the 2003 update. Canadian Medical Association Journal, 169(9): 921–924. Also available online: http://www.cmaj.ca/cgi/content/full/169/9/921/DC1. Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins. Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.
    • Cholesterol, Total (also see Lipid Screening)Cholesterol is a major predictor of coronary artery disease. The National Cholesterol Education Programrecommends that every adult have a total serum cholesterol and that other nonlipid coronary heartdisease risk factors be assessed. Cholesterol tends to be higher in the winter than in the summer.Lipid levels are interpreted as follows: Lipid Level (mg/dL) Interpretation <200 Desirable Cholesterol Level 200 - 239 Borderline Cholesterol Level >240 High Cholesterol LevelIf cholesterol is less than 200 mg/dL, testing should be repeated within five years or during the nextphysical examination. If cholesterol is between 200 and 239 mg/dL, and less than two risk factors arepresent the cholesterol should be repeated annually. If cholesterol is above 240 mg/dL or two or morerisk factors are present, lipoprotein analysis should be done. All cholesterol levels above 200 mg/dLshould be confirmed by repeat measurement and the average used to guide clinical decisions. Seelipoprotein analysis.Specimen requirement is one SST tube of blood collected after an overnight fast.Cholesterol, HDLSee HDL cholesterol and Lipid ScreeningCholesterol, LDLSee LDL Cholesterol and Lipid Screening
    • LDL CholesterolA lipid panel is commonly ordered to assess the risk of coronary artery disease. This panel consists ofmeasured total cholesterol, HDL cholesterol, and triglycerides and calculated LDL cholesterol. The latteris calculated using the Friedewald equation: LDL cholesterol = Total cholesterol - (HDL cholesterol +triglycerides/5). This equation assumes that the amount of cholesterol in very low density lipoproteins(VLDL) can be accurately estimated by dividing triglyceride concentration by a factor of five. In themajority of cases, this assumption is valid and calculated LDL cholesterol levels are accurate. However,the Friedewald equation does have limitations and should not be used in three situations: [1] whenchylomicrons are present (e.g. nonfasting state and Type I &V hyperlipoproteinemias) , [2] whentriglyceride concentrations exceed 400 mg/dL, and [3] when patients have dysbetalipoproteinemia (typeIII hyperlipoproteinemia, incidence of 1 in 1000 individuals). In the first two situations, LDL cholesterolwill be underestimated and in the third situation it will be overestimated. LDL cholesterol levelscalculated on nonfasting specimens may be 10 to 20% lower than fasting results.Another option is to directly measure LDL cholesterol by the beta quant method, which involvesultracentrifugation and polyanion precipitation. Because of the increased expense of this and the limitedreimbursement for LDL cholesterol, it is not feasible to screen all sera with this method. Initial screeningshould be done with calculated LDL cholesterol. Sera will be retained in the laboratory for two weeks. Iftriglycerides are greater than 400 mg/dL or Type I, III or Type V hyperlipoproteinemia is suspected,Direct LDL cholesterol can be ordered and performed on the original specimen.
    • Lipid VariabilityLipid and lipoprotein concentrations vary during the normal course of daily activity. Studies havedemonstrated that within person variability is sufficient to make an individual move in and out of thepredefined risk categories defined by the National Cholesterol Education Program (NCEP). As many as 11% ofpatients would be mistreated if risk assessment were made on the basis of a single lipid panel. NCEPguidelines acknowledge this variation by stressing that patient management decisions should be based on anaverage of at least two results. The extent of within person biological variability (expressed as the coefficientof variation) for each lipid fraction is summarized in the following table. Interval Total- HDL-C LDL-C TG C Day 2.5% 4.5% 7.8% 36% Month 4.8% 7.7% 9.6% 24% Year 6.1% 8.4% 13.6% 26%Triglycerides fluctuate widely, even during a single day, because they exhibit diurnal variation. Triglycerideconcentration is lowest at 3 a.m., rises until mid-afternoon and decreases thereafter. Cholesterol and LDLcholesterol are not subject to diurnal variation, but are affected by seasonal variation. Levels increase asmuch as 5% in winter. Other sources of intra-individual variation are listed below. Variable Effect Menstruation 6-9% TC increase in follicular phase Pregnancy 30% TC & 200% TG increase at term Acute illness 15% TC & 25% HDL decrease Weight loss 10% TC, 10% HDL, 40% TG decrease Exercise 3-7% TC decrease & 3-10% HDL increase Smoking 3% TC & 9% TG increase, 6- 11% HDL decrease Posture 10-20% higher standing than lying Specimen Stable for 3 days handlingBesides biological variation, lipid values are also dependent on the laboratorys analytical performance.Todays chemistry analyzers are very precise; analytical variation in reputable laboratories is less than onehalf of biological variation. The coefficient of variation at Saint Lukes Hospital Laboratory is 2.2% forcholesterol, 3.8% for HDL cholesterol and 4.2% for triglycerides. Combining biological and analyticalvariability, it is possible to calculate the magnitude of change that must occur to have 95% confidence that achange in lipid value is medically significant.
    • Lipid Result Significant (mg/dL) ChangeCholesterol 180 32 200 35 220 39 240 43 260 46 280 50 300 53HDL 25 7 30 8 35 10 40 11 45 12 50 14 55 15 60 16 65 18Triglycerides 100 84 150 126 200 168 250 210 300 252 350 293 400 336 450 378 500 420
    • Cholesterol concentration must change at least 18%, HDL cholesterol 27% and triglycerides 84% before onecan be assured that the difference is not simply due to intra-individual and analytical changes.
    • Lipid PanelElevated LDL cholesterol is a major cause of coronary heart disease (CHD). Recent clinical trials haveconvincingly demonstrated that LDL lowering therapy reduces the risk for CHD. The National CholesterolEducation Programs (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High BloodCholesterol in Adults recently published their updated clinical guideline for cholesterol testing andmanagement (JAMA 2001; 285:2486), which is referred to as the Adult Treatment Panel III (ATP III).ATP III recommends intensive treatment for patients with CHD and primary prevention in persons withmultiple risk factors.The new guideline recommends that a fasting lipid panel should be obtained once every 5 years for alladults aged 20 years or older. The panel should include total cholesterol, LDL cholesterol, HDLcholesterol and triglycerides. The new guideline also states that a lipid panel should be ordered within 24hours of admission when patients are hospitalized for acute coronary syndromes or coronary proceduresto guide initiation of LDL lowering therapy prior to discharge.ATP III differs significantly from ATPII, which was published in 1993, in the interpretation of lipid levels.  The optimal LDL cholesterol level was lowered from 130 to 100 mg/dL.  The lower limit of normal for HDL cholesterol was raised from 35 to 40 mg/dL.  The optimal triglyceride level was decreased from 200 to 150 mg/dL.Because of these changes, lipid values are now interpreted as follows. ATP III Classification of Lipid Values Total cholesterol Desirable <200 Borderline high 200 - 239 High >239 LDL cholesterol Optimal <100 Above optimal 100 - 129 Borderline High 130 - 159 High 160 - 189 Very High >189 HDL cholesterol Low <40 High >59 Triglycerides Normal <150 Borderline High 150 - 199 High 200 - 499 Very High >499Consistent with the two previous consensus statements, ATP III continues to identify elevated LDLcholesterol as the primary target of cholesterol lowering therapy. Thus, the first step in assessing apatients risk is to determine their LDL cholesterol level. The second step is to determine if the patient
    • has any additional risk determinants such as the presence or absence of CHD, other clinical forms ofatherosclerotic disease (peripheral arterial disease, abdominal aortic aneurysm, & carotid artery disease)diabetes mellitus and the following major risk factors.  Cigarette smoking  Hypertension (BP > 140/90) or anti-hypertensive medication  Low HDL cholesterol ( < 40 mg/dL)  Family history of premature CHD (1st degree relative male < 55 or female < 65 years)  Age (men > 44 years & women > 55 years)Based on these other risk determinants, ATP III identifies 3 categories of risk that modify the goals ofLDL cholesterol lowering therapy. Risk Category LDL Goal (mg/dL) CHD & Equivalents <100 Multiple (2+) risk factors <130 0 - 1 risk factor <160The relationship between LDL cholesterol levels and CHD risk is continuous over a broad range of LDLlevels. An LDL cholesterol level of < 100 mg/dL is optimal. Therefore, ATP III specifies that the goal oftherapy for secondary prevention in persons with CHD or CHD risk equivalents is < 100 mg/dL. Diabetesand peripheral vascular disease are now considered risk equivalents to CHD, because patients with thesediseases have at least a 20% chance of experiencing a major coronary event within 10 years.LDL goals in primary prevention depend on a persons absolute risk for CHD. Individuals without CHD,diabetes or peripheral vascular disease who have 2 or more risk factors have a 10 to 20% of developinga major coronary event in the next 10 years. Their LDL treatment goal is < 130 mg/dL. Persons with 1or less risk factors have a 10 year coronary risk of < 10% and need to reduce their LDL cholesterolbelow 160 mg/dL.Many other lifestyle risk factors are known to be independent risk factors for CHD including obesity,physical inactivity, atherogenic diet, impaired glucose tolerance, lipoprotein (a), homocysteine,fibrinogen, and high sensitivity C-reactive protein. However, these factors were not used to set a lowerLDL cholesterol goal of therapy.Low HDL cholesterol is a strong independent predictor of CHD and is considered to be a major riskfactor. In ATP III, low HDL cholesterol is defined as a level below 40 mg/dL, which is a change from thelevel of < 35 mg/dL specified in ATP II. Most commonly, low HDL cholesterol is combined with hightriglycerides. This combination is most often associated with insulin resistance. ATP III does not specifya therapeutic goal for raising HDL; instead the emphasis is on reducing LDL cholesterol. Treatment ofisolated low HDL is mostly reserved for persons with CHD or CHD risk equivalents.Recent meta-analyses of prospective studies indicate that elevated triglycerides are also an independentrisk factor for CHD. For all persons with borderline or high triglycerides, the primary aim of therapy is toachieve the target goal for LDL cholesterol. Borderline triglyceride levels often decrease with weightreduction or increased physical activity. High triglyceride levels may require additional drug therapy withnicotinic acid or fibrates.The reference ranges for each lipid fraction is: Current New Total cholesterol <200 <200 LDL cholesterol <130 <100 HDL cholesterol >35 >40 Triglycerides <150 <150
    • Lipoprotein a Cholesterol, Lp(a)Lipoprotein (a) is a modified form of LDL to which another glycoprotein, termed apolipoprotein (a), iscovalently bound. It contributes to atherogenic risk by multiple mechanisms that include inhibition offibrinolysis, increased cholesterol deposition in the arterial wall, and enhanced oxidation of LDLcholesterol. The evidence linking Lp(a) levels and the risk of coronary disease is strongest for middleaged white men. Higher Lp(a) levels have been consistently observed in white and Asian groups withvascular disease, but not in African Americans.Environmental and racial factors may modulate Lp(a) concentrations. Levels are higher in Africans,African Americans, postmenopausal women and patients with hypercholesterolemia. Lp(a) levels areincreased in renal insufficiency, in the nephrotic syndrome, after kidney transplantation, and in patientsundergoing hemodialysis or peritoneal dialysis. Levels can increase dramatically after coronary ischemiaand surgery because Lp(a) is an acute phase reactant. Lp(a) fluctuates during hormonal changes thatoccur in patients with diabetes mellitus, estrogen therapy, and pregnancy. Lower levels are seen inindividuals with higher estrogen or androgen levels, cirrhosis, and alcoholism. Exercise and low fat dietsdo not significantly lower Lp(a).Measurement of Lp(a) provides only modest assistance to the physician caring for patients at risk ofcoronary artery disease. Lp(a) is an independent but relatively weak predictor of coronary artery diseasein unselected populations, but is a powerful predictor of premature CAD, especially in patients withconcomitant hypercholesterolemia. Lp(a) testing should be reserved for individuals with prematuremyocardial infarction and a relatively normal risk factor profile, a strong family history of prematureatherosclerosis not explained by other dyslipidemias, or patients with refractory hypercholesterolemia.Estrogen replacement therapy is the first line treatment for postmenopausal women and nicotinic acid isthe first choice for men. The goal for pharmacologic therapy for white populations is a Lp(a) level of lessthan 30 mg/dL. Intra-individual variability is 15%.Estrogen and progestin have been found to lower Lp(a) levels in postmenopausal women. The Heart andEstrogen/progestin Replacement Study (HERS) determined the relationships among treatment withestrogen and progestin, plasma Lp(a) levels and subsequent coronary heart disease in 2763postmenopausal women with coronary artery disease (JAMA2000;283:1845-52). Ninety two percent ofwomen were White and 8% were African American. Women were divided into quartiles based on Lp(a)level at enrollment. Increased baseline Lp(a) levels among women in the placebo arm of the study wereassociated with subsequent coronary heart disease, death or nonfatal myocardial infarction. Women inthe third and fourth quartiles of baseline Lp(a) level had an increased relative risk compared to womenin the lowest quartile. Quartile Lp(a) mg/dL Relative Risk 1 0 - 7.0 1.00 2 7.1 - 25.3 1.01 3 25.4 - 54.9 1.31 4 55 - 236 1.54Estrogen and progestin therapy reduced mean Lp(a) levels by 15 mg/dL for women in the third andfourth quartiles and reduced the risk of secondary coronary events by 15 to 20%. This data suggeststhat Lp(a) is an independent risk factor for recurrent coronary heart disease in postmenopausal womenand that treatment with estrogen and progestin lowers Lp(a) levels. Estrogen and progestin therapyappears to have a more favorable effect in women with high initial Lp(a) levels than in women with lowlevels.Recently, two pediatric studies linked elevated Lp(a) levels to childhood venous thromboembolism. Arecent study evaluated the role of Lp(a) as a risk factor for venous thrombosis in adults (Blood, 96:3364-3368, 2000). A total of 685 consecutive subjects with a history of venous thromboembolism (menand women, aged 11-77) were screened for prothrombotic risk factors, including Lp(a), and comparedwith 266 age- and sex-matched healthy controls. Elevated Lp(a) levels >30 mg/dL were present in 20%of the patients and 7% of the controls, and were associated with a 3.2-fold increased risk of thrombosis.An increased risk of thrombosis was even seen for Lp(a) levels >20 mg/dL (2.2-fold increased risk),
    • compatible with a concentration-dependent risk starting at Lp(a) levels within the normal range. In thisstudy, Factor V Leiden (the most common hereditary prothrombotic risk factor) was associated with a5.7-fold increased risk of thrombosis. Coexistence of Lp(a) >30 mg/dL with factor V Leiden was found in7% of the patients, and only 0.8% of controls, and the combination was associated with a 9.8-foldincreased risk of venous thromboembolism.These findings suggest that Lp(a) elevation is a frequent and independent risk factor for venousthromboembolism. Furthermore, elevated Lp(a) levels may contribute to the thrombotic risk associatedwith factor V Leiden and other hereditary or acquired prothrombotic risk factors, compatible with thewidely accepted concept that venous thrombosis is a multicausal disorder.Reference range is: Population Reference Range African American 22-74 mg/dL Caucasian 6-34 mg/dLSpecimen requirement is one SST tube of blood.
    • Lipoprint LDL Subfractions Elevated low density lipoprotein cholesterol (LDL-C) is a well-known risk factor for coronary heart disease(CHD). The National Cholesterol Education Programs Adult Treatment Panel recommends LDL-C levels be less than 100 mg/dL for patients with known CHD or with CHD Risk Equivalents such as type 2 diabetes mellitus,symptomatic carotid artery disease, or multiple CHD risk factors. As important as LDL-C is as a risk predictor, there are still many patients who have LDL-C levels less than 130 mg/dL but still have heart attacks. Patients with high triglycerides and low HDL-C are especially likely to have atherogenic dyslipidemia which also includes mild elevations in LDL-C and the presence of small, dense LDL particles. Recent evidence has suggested that a preponderance of small LDL particles may be an independent risk factor for CHD. A recentpaper from the Diabetes Atherosclerosis Intervention Study group found that in patients with LDL-C of < 115g/dL, progression of coronary artery disease was nearly 4 times greater in those with small LDL than in those with large LDL. Patients with small LDL had an equivalent risk for progression as those with LDL-C > 140 mg/dL (Vakkilainen et al. Circulation 2003;107:1733). Although the NCEP does not currently recommend measuring LDL subfractions as a screening tool, it does acknowledge that detection of small LDL is a useful indicator of atherogenic dyslipidemia and the metabolicsyndrome. The presence of small LDL particles also supports intensified therapeutic lifestyle changes. If small LDL particles accompany elevated triglycerides or low HDL-C in high risk persons, nicotinic acid or fibric acid derivatives can be included as a component of lipid lowering therapy (NCEP ATPIII Report, p. II-33). Lipoprint is the only FDA-approved test for measuring LDL subfraction cholesterol levels. It reports out the LDL phenotype as type A, intermediate, or type B based on particle size. Pattern A indicates lower risk and pattern B higher risk for CHD. Sample requirement is 1 mL of serum or EDTA plasma. CPT code is 83716.
    • Alanine Aminotransferase (ALT)(SGPT) Test OverviewAn alanine aminotransferase (ALT) test measures the amount of this enzyme in the blood. ALT is found mainly in theliver, but also in smaller amounts in the kidneys , heart , muscles, and pancreas . ALT formerly was calledserum glutamic pyruvic transaminase (SGPT).ALT is measured to see if the liver is damaged or diseased. Low levels of ALT are normally found in the blood.However, when the liver is damaged or diseased, it releases ALT into the bloodstream, which makes ALT levels go up.Most increases in ALT levels are caused by liver damage.The ALT test is often done along with other tests that check for liver damage, including aspartate aminotransferase(AST), alkaline phosphatase, lactate dehydrogenase (LDH), and bilirubin. Both ALT and AST levels are reliable tests forliver damage.Why It Is DoneThe alanine aminotransferase (ALT) test is done to:  Identify liver disease, especially cirrhosis and hepatitis caused by alcohol, drugs, or viruses.  Help check for liver damage.  Find out whether jaundice was caused by a blood disorder or liver disease.  Keep track of the effects of cholesterol-lowering and other medications that can damage the liver.How To PrepareAvoid strenuous exercise just before having an ALT test.Tell your doctor if you:  Are taking any medicines. Many medicines can interfere with test results. Your health professional may instruct you to stop taking certain medicines for several days before having an ALT test. Some herbs and natural products (such as echinacea and valerian) also can affect ALT results.  Are allergic to any medicines.  Are or might be pregnant.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results may mean. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneThe health professional taking a sample of your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Put a gauze pad or cotton ball over the needle site as the needle is removed.  Put pressure on the site and then put on a bandage.How It FeelsThe blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight.You may feel nothing at all from the needle, or you may feel a quick sting or pinch.RisksThere is very little chance of a problem from having blood sample taken from a vein.
    •  You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.  In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.  Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicines, tell your doctor before your blood sample is taken.ResultsAn alanine aminotransferase (ALT) test measures the amount of this enzyme in the blood. Results are usually availablewithin 12 hours.NormalNormal results may vary from lab to lab. Alanine aminotransferase 4–36 units per liter (U/L) or 4–36 international units per liter (IU/L)High valuesVery high levels of ALT may be caused by:  Recent or severe liver damage, such as viral hepatitis.  Lead poisoning.  Drug reactions.  Exposure to carbon tetrachloride.  Decay of a large tumor (necrosis).  Shock.Mildly or moderately high ALT levels may be caused by:  Mononucleosis.  Hepatitis. The ALT level in a person with hepatitis can be 20 times the normal value.  Alcohol dependence. People who drink excessive amounts of alcohol and take acetaminophen (such as Tylenol) can have high ALT blood levels.  Mildly elevated levels of ALT may occur in people who are growing quickly, especially young children.Slightly high levels ALT levels may be caused by:  Cirrhosis.  Liver cancer.  A heart attack.  Thyroid disease.  Polymyositis.  Severe burns.  Injury to the pancreas, kidneys, or muscles.  Vigorous exercise.  Many medicines, such as antibiotics, chemotherapy, aspirin, narcotics, and barbiturates.What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  Taking medicines. Talk with your health professional about all the prescription and nonprescription medicines you are taking. You may be instructed to stop taking your medicines for several days before the test.  Taking some herbs and natural products, such as echinacea and valerian.  Strenuous exercise, injury to a muscle, or injections into a muscle.  Recent cardiac catheterization or surgery.
    • What To Think About  The alanine aminotransferase (ALT) value is often used along with the results of the aspartate aminotransferase (AST) test to obtain the AST to ALT ratio. This value can often help determine whether there is damage to the liver related to alcohol dependence. For more information, see the medical test Aspartate Aminotransferase (AST).  In children with acute lymphocytic leukemia (ALL), very high ALT levels may mean that the disease is likely to progress rapidly.  Many different conditions can raise ALT blood levels. Therefore, other testing is usually needed to interpret an abnormal ALT result.ReferencesOther Works Consulted  Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.  Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.  Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.  Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis:
    • Aspartate Aminotransferase (AST) (SGOT) Test OverviewAn aspartate aminotransferase (AST) test measures the amount of this enzyme in the blood. AST is normally found inred blood cells, liver, heart, muscle tissue, pancreas, and kidneys. AST formerly was called serum glutamic oxaloacetictransaminase (SGOT).Low levels of AST are normally found in the blood. When body tissue or an organ such as the heart or liver is diseasedor damaged, additional AST is released into the bloodstream. The amount of AST in the blood is directly related to theextent of the tissue damage. After severe damage, AST levels rise in 6 to 10 hours and remain high for about 4 days.The AST test may be done at the same time as a test for alanine aminotransferase, or ALT. The ratio of AST to ALTsometimes can help determine whether the liver or another organ has been damaged. Both ALT and AST levels cantest for liver damage.Why It Is DoneAn aspartate aminotransferase (AST) test is done to:  Help find the cause of liver damage.  Help identify liver disease, especially hepatitis and cirrhosis. Liver disease may produce symptoms such as pain in the upper abdomen, nausea, vomiting, and sometimes jaundice.  Check on the recovery from or treatment for liver disease.How To PrepareTo prepare for an aspartate aminotransferase (AST) test:  Avoid strenuous exercise just before having this test done.Tell your doctor if you:  Are taking any medicines. Many medicines can interfere with test results. Your health professional may instruct you to stop taking certain medicines for several days before having an AST test. Some herbs and natural products (such as echinacea and valerian) also can affect AST results.  Are allergic to any medicines.  Are or might be pregnant.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results may mean. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneThe health professional taking a sample of your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Put a gauze pad or cotton ball over the needle site as the needle is removed.  Put pressure on the site and then put on a bandage.How It FeelsThe blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight.You may feel nothing at all from the needle, or you may feel a quick sting or pinch.Risks
    • There is very little chance of a problem from having blood sample taken from a vein.  You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.  In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.  Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.ResultsAn aspartate aminotransferase (AST) test measures the amount of this enzyme in the blood. Results are usuallyavailable within 12 hours.NormalNormal values may vary from lab to lab. Aspartate aminotransferase (AST)8–35 units per liter (U/L) or 5–40 international units per liter (IU/L)High valuesVery high levels of AST may be caused by:  Recent or severe liver damage, such as hepatitis caused by a viral infection or drug reaction.  Decay of a large tumor (necrosis).  Shock.Moderately high levels of AST may be caused by:  A heart attack or heart failure.  Alcohol abuse.  Having taken high doses of vitamin A.  Kidney or lung damage.  Liver damage, such as from cirrhosis.  Mononucleosis.  Duchenne muscular dystrophy.  Some types of cancer.  A rare autoimmune disease that affects muscles (myositis).Slightly high levels of AST may be caused by:  A heart attack or heart failure.  Hemolytic anemia, such as that caused by sickle cell anemia or a reaction to blood transfusion.  Cancer.  Pancreatitis.AST levels may be high when a disease first develops, which is often when tissue damage is most severe. Decreasinglevels of AST in the blood may be a sign of recovery from the disease or injury.Many other conditions, including severe burns, traumatic injuries, pulmonary embolism, or heat exhaustion andheatstroke, and ingestion of poisonous mushrooms may cause elevated AST levels.What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:
    •  Taking medicines. Talk with your health professional about all the prescription and nonprescription medicines you are taking. You may be instructed to stop taking your medicines for several days before the test.  Taking large doses of vitamin A.  Taking some herbs and natural products, such as echinacea and valerian.  Strenuous exercise, injury to a muscle, or injections into a muscle.  Recent cardiac catheterization or surgery.What To Think About  The aspartate aminotransferase (AST) test is more effective than the alanine aminotransferase (ALT) test for detecting liver damage caused by alcohol dependence. The AST to ALT ratio may sometimes help determine if liver damage is related to alcohol dependence. For more information, see the medical test Alanine Aminotransferase (ALT).  Many different conditions can raise AST blood levels. Therefore, other testing is usually needed to interpret an abnormal AST result.
    • AlbuminAlbumin comprises 60% of the total serum protein and 60 to 80% of colloid osmotic pressure. Serumalbumin is synthesized solely by the liver and has several physiological functions: transport of lowmolecular weight substances such as calcium, hormones, and drugs; binding of toxic heavy metal ions;maintenance of colloid osmotic pressure; and provision of a protein reserve. Normally, about 4% of thetotal body albumin is replenished each day. The rate of production is dependent on the supply of aminoacids, plasma oncotic pressure, inhibitory cytokine (especially IL-6) concentration, and the number offunctioning hepatocytes. Circulating half-life of plasma albumin is 19 to 21 days.Plasma albumin levels are low in neonates, typically between 2.8 and 4.4 g/dL. Adult levels are reachedafter the first week of life. Levels are slightly higher in children (4.5 - 5.5 g/dL) between the age of 6years and young adulthood. Thereafter, levels decline to typical adult levels. Albumin levels show adownward trend throughout pregnancy and with aging, especially after age 70. Serum albumin levelsare normally lower in hospitalized than ambulatory patients. Albumin levels can decrease as much as 1g/dL after a patient becomes recumbent. Albumin concentration may decrease after crystalloid infusionor in patients with fluid retention. Falsely low values will be obtained if a blood sample is drawn abovean IV site.Hypoalbuminemia can be caused by many different disease states. The main causes include:  Protein loss (nephrotic syndrome, burns, protein losing enteropathy)  Transcapillary leak into the interstitial fluid  Chronic liver diseasePlasma albumin is seldom decreased in acute hepatitis, because of its long circulating half-life.Decreased serum albumin usually indicates liver disease of more than 3 weeks duration. Albumin is agood indicator of decompensation and prognosis in cirrhosis.Plasma albumin is of virtually no value in assessment or monitoring of nutritional status. The primarycause of decreasing plasma albumin concentration in sick hospitalized patients is transcapillary escapeinto the interstitial fluid as a result of the systemic inflammatory response syndrome (SIRS).Postoperative patients and patients with severe infection inevitably have low plasma albumin. The moresevere the disease is, the lower the albumin, and therefore the lower the albumin, the worse theprognosis. Hypo-albuminemia is associated with poor surgical outcome and increased length of stay.Serum albumin levels less than 2 g/dL are associated with a 60% thirty-day mortality rate.Abnormally high albumin levels are seldom clinically important. Increased serum albumin levels are seenonly with dehydration or after excessive albumin infusion. Artefactual causes of high levels includespecimen evaporation and prolonged use of a tourniquet during venipuncture.Reference range is 3.5 - 5.0 gm/dL
    • Total Serum Protein Test OverviewA total serum protein test measures the total amount of protein in the blood. Two major groups of proteins in the bloodare albumin and globulin.  Albumin is made mainly in the liver. It helps keep the blood from leaking out of blood vessels. Albumin also helps carry some medicines and other substances through the blood and is important for tissue growth and healing.  Globulin is made up of different proteins called alpha, beta, and gamma types. Some globulins are made by the liver, while others are made by the immune system. Certain globulins bind with hemoglobin. Other globulins transport metals, such as iron, in the blood and help fight infection. Serum globulin can be separated into several subgroups by serum protein electrophoresis. For more information, see the medical test Serum Protein Electrophoresis.Why It Is DoneAlbumin is tested to:  Check how well the liver and kidney are working.  Find out if your diet contains enough protein.  Help determine the cause of swelling of the ankles (pedal edema) or abdomen (ascites) or of fluid collection in the lungs that may cause shortness of breath (pulmonary edema).Globulin is tested to:  Determine your chances of developing an infection.  See if you have a rare blood disease, such as multiple myeloma or macroglobulinemia.How To PrepareNo special preparation is required before having a total serum protein test.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results may mean. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneThe health professional taking a sample of your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Put a gauze pad or cotton ball over the needle site as the needle is removed.  Put pressure on the site and then put on a bandage.How It FeelsThe blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight.You may feel nothing at all from the needle, or you may feel a quick sting or pinch.RisksThere is very little chance of a problem from having blood sample taken from a vein.  You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
    •  In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.  Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.ResultsA total serum protein test is a blood test that measures the total amount of protein in the blood. Results are usuallyavailable within 12 hours.NormalNormal values may vary from lab to lab. Total serum proteinTotal protein: 5.5–9.0 grams per deciliter (g/dL)Albumin: 3.5–5.5 g/dLGlobulin: 2.0–3.5 g/dLAlbumin/globulin ratio: Greater than 1.0High valuesHigh albumin levels may be caused by:  Severe dehydration.High globulin levels may be caused by:  Diseases of the blood, such as multiple myeloma, Hodgkins lymphoma, leukemia, macroglobulinemia, or hemolytic anemia.  An autoimmune disease, such as rheumatoid arthritis, lupus, autoimmune hepatitis, or sarcoidosis.  Kidney disease.  Liver disease.  Tuberculosis.Low valuesLow albumin levels may be caused by:  A poor diet (malnutrition).  Severe burns.  Kidney disease.  Liver disease.  An autoimmune disease, such as systemic lupus erythematosus (SLE) or rheumatoid arthritis.  Gastrointestinal malabsorption syndromes, such as sprue or Crohns disease.  Hodgkins lymphoma.  Uncontrolled diabetes.  Hyperthyroidism.  Heart failure.What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  Taking medicines, such as corticosteroids, estrogens, male sex hormones (called androgens), growth hormone, or insulin.  Injuries or infections.  Prolonged bed rest, such as during a hospital stay.
    •  A long-term (chronic) illness, especially if the disease interferes with what you are able to eat or drink.  Being pregnant.What To Think About  If you have abnormal globulin levels, another test called serum protein electrophoresis is often done. This test measures specific groups of proteins in the blood. For more information, see the medical test Serum Protein Electrophoresis.  Damaged liver cells lose their ability to make protein. However, previously produced protein may stay in the blood for 12 to 18 days. Therefore, it takes about 2 weeks for damage to the liver to show up as decreased serum protein levels. The livers ability to make protein may be used to predict the course of certain liver diseases.  Unlike carbohydrates and fats, proteins are not stored in the body. They are continuously broken down (metabolized) into amino acids that can be used to make new proteins, hormones, enzymes, and other compounds needed by the body.  Protein also can be measured in the urine. For more information, see the medical test Urine Test.ReferencesOther Works Consulted  Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.  Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.  Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.  Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.
    • Protein Total SerumTotal serum protein is the sum of the concentration of the circulating proteins. Changes in total proteinconcentration may reflect changes in one, several or all fractions. The clinical significance of a change intotal protein is difficult to interpret without knowledge of the level of the individual protein fractions, asdetermined by serum protein electrophoresis. Causes of increased total protein include chronic infection,liver disease, autoimmune disease, sarcoidosis, monoclonal gammopathies, dehydration, and hemolysis.Total protein is decreased in malnutrition, liver disease, renal disease, nephrotic syndrome,malabsorption, protein losing enteropathy, exfoliative dermatitis, burns, hypogammaglobulinemia, IVfluids, and pregnancy. Total serum protein level is higher in ambulatory than recumbent patients.Reference range is 6.5 - 8.2 gm/dL.Specimen requirement is one SST tube of blood.
    • Protein C is a vitamin KProtein C is a vitamin K dependent plasma protein that inhibits coagulation. For Protein C to serve as ananticoagulant, it must be converted to its active form (Protein Ca) by thrombin. After activation itpotently inhibits coagulation by inactivating Factors V and VIII, and enhances fibrinolysis by neutralizingan inhibitor of plasminogen activator.Most affected individuals are teenagers or young adults who are heterozygous for the deficiency.Homozygous individuals usually do not survive the neonatal period. The clinical syndromes associatedwith hereditary deficiency of Protein C include:  recurrent venous thromboembolism  warfarin skin necrosis  purpura fulminans in neonatesIndications for Protein C assay include the investigation of any patient with unexplainedthromboembolism, especially venous, particularly if thrombotic episodes:  occur at a relatively young age  are recurrent  are associated with a positive family history of thrombotic diseaseOver 60 families have been described with Protein C deficiency. Affected heterozygous family membershave Protein C levels between 40 and 65% of normal, associated with an increased incidence ofthromboembolic disease (predominantly venous). It appears, however, that most subjects withheterozygous Protein C deficiency are asymptomatic. Perhaps an additional as yet unidentified risk factorexists in those subjects who develop thrombosis.Skin necrosis may develop in patients with reduced Protein C levels at the beginning of warfarin therapy.This is due to a transient hypercoagulable state following the rapid warfarin-induced fall in Protein Clevels, before the levels of Factors II, IX, and X decrease.Neonates with homozygous Protein C deficiency (Protein C levels close to zero) present with an oftenfatal syndrome of purpura fulminans with spreading skin necrosis, thrombosis and disseminatedintravascular coagulation (DIC).Acquired Protein C deficiency may be seen in a wide variety of clinical situations including DIC, extensivethrombosis, liver disease, after surgery, and malignancy. It is uncertain whether or not acquireddeficiency contributes to a thrombotic tendency. Since acquired deficiencies of Protein C occur frequentlyin hospitalized patients, it is preferable to perform the assays at a time when the patient is in stablecondition, and ideally in remission from thrombotic events.Since Protein C is a vitamin K dependent protein, decreased levels may be expected if a patient is onoral anticoagulant drug therapy. Testing for protein C should be deferred until a patient has been off oralanticoagulants for at least 10 days. If it is not possible to discontinue oral anticoagulants and protein Cassay is felt to be essential, consideration should be given to stopping the warfarin for 10 days prior tothe assays while the patient is temporarily covered with heparin (standard or low molecular weight).Reference range is 70 - 140% for the functional assay and 65 - 140% for the antigenic assay. A ProteinC level of less than 55% is usually indicative of hereditary deficiency in a stable non-anticoagulatedadult. A level of 55-65% may indicate either a low normal value or mild hereditary deficiency. Ingeneral, a diagnosis of hereditary deficiency of Protein C should only be made when a low value hasbeen obtained after repeated testing (after a 4-6 week interval), and the possibility of acquireddeficiency has been excluded. Testing of family members may be helpful in confirming the diagnosis.Specimen requirement is one light blue top (sodium citrate) tube of blood.
    • Protein Electrophoresis SerumSerum proteins have different net charges and can be separated by electrophoresis into several distinctbands; albumin, alpha 1-globulin (a1G), alpha 2-globulin (a2G), beta globulin (bG), and gamma globulins(gG). Protein concentrations may be altered as a result of different disease states. Interpretation of serumprotein electrophoretic patterns is helpful in confirming the diagnosis of some diseases. The most commonlyrecognized electrophoretic patterns are summarized in the following table. Pattern Protein Changes Frequently Associated Diseases Acute Normal or Decreased Acute infection and inflammatory albumin disorders Inflammation Increased a1 &/or a2Globulin Chronic Normal or Decreased Autoimmune diseases, chronic albumin liver disease, chronic infection, Inflammation cancer Increased a1G or a2Globulin Increased gamma Globulin Hypoalbuminemia Decreased albumin Metastatic cancer, CHF, malnutrition, protein losing disorders Hypogamma- Normal or Decreased Lymphoproliferative disorders, globulinemia albumin inflammatory bowel disease, congenital immunodeficiencies Decreased gamma Globulin Polyclonal Increased gamma Globulin Autoimmune disease, infections, gammopathy Liver disease Cirrhosis Increased gamma Globulin Cirrhosis Beta-gamma bridging Protein losing Decreased albumin Nephrotic syndrome, exudative disorder skin disorders, Decreased a1Globulin gastroenterophathies, Increased a2Globulin Increased bGlobulin Monoclonal Normal or Decreased Myeloma, macroglobulinemia, gammopathy albumin MGUS, CLL, lymphoma Increased gamma Globulin Antitrypsin Absent a1Globulin Alpha 1 antitrypsin deficiency deficiency Hyperbeta- Normal - Decreased Hyperlipidemia, diabetes mellitus, albumin globulinemia iron deficiency anemia
    • Increased beta GlobulinSPE Interpretation Tips  Albumin band often looks less intense on IFE compare to SPE, probably because it is incompletely fixed and elutes off the gel  Bilirubin, heparin & antibiotic binding can cause slurring of albumin band  Hemolysis causes decreased alpha-2 band (haptoglobin) and appearance of hemoglobin band between alpha-2 and beta-1 regions  C3 is labile & decreases with storage; results in much variation in beta-2 region  Fibrinogen migrates between beta-2 and gamma regions (close to application point) and is present in plasma or heparin contaminated specimens  Immune complexes appear as monoclonal band at application point  Monoclonal bands in the beta region may indicate light chain disease, amyloidosis, heavy chain disease, IgD and IgE monoclonal gammopathies  Gamma heavy chain disease can produce a relatively broad band anywhere from the alpha-2 through the gamma region  CRP migrates in the gamma region and resembles a monoclonal band; present in acute inflammation  High resolution SPE gel can detect a monoclonal band of 0.1 g/dL  Oligoclonal bands with hypergammaglobulinemia & possibly beta-gamma bridging may be present in serum in patients responding to antigenic stimulation resulting from viral & bacterial infections, vaccines, autoimmune diseases and angioimmunoblastic lymphadenopathy  Oligoclonal bands with decreased IgG level is seen in CLL, post heart and BM transplants, and common variable immunodeficiency and immunosuppressive Rx  Infections may cause transient monoclonal proteins  Light chain disease can result in monoclonal kappa or lambda chains in serum and not in urine if light chains are polymerized  Kappa chains usually stain more strongly than lambda chains  Broader width of monoclonal bands may be related to amount of protein applied to gel or heterogeneity of monoclonal protein due to glycosylation. IgA monoclonal bands are usually broader than IgG  A monoclonal band may be clinically significant if it is at least as intense as the alpha 1 band  Clues that a monoclonal band is unlikely to be due to a malignant clonal expansion  Acute phase pattern is present along with monoclonal band  Monoclonal band is transient & may evolve into an oligoclonal pattern  All immunoglobulin classes are elevated along with monoclonal  Slightly abnormal kappa:lambda ratio  Bence Jones protein is absent from urineSerum protein electrophoresis should be repeated in one year for asymptomatic patients with a monoclonalprotein less than 1.5 g/dL and normal values of hemoglobin, calcium, and creatinine. Electrophoresis shouldbe repeated in two to three months if the monoclonal protein is between 1.5 and 2.5 g/dL. Patients beingtreated for multiple myeloma, Waldenstroms macroglobulinemia or amyloidosis should be monitored at oneto two month intervals.Reference ranges are: Total protein 6.0 - 8.0 g/dL Albumin 3.5 - 5.0 g/dL Alpha 1 globulin 0.1 - 0.4 g/dL Alpha 2 globulin 0.4 - 1.3 g/dL Beta globulin 0.6 - 1.3 g/dL Gamma globulin 0.6 - 1.5 g/dLSpecimen requirement is one SST tube of blood.
    • Protein Total Spinal Fluid(see also Multiple Sclerosis Panel)Spinal fluid is an ultrafiltrate of plasma that lacks high molecular weight proteins such as betalipoprotein, alpha-2 macroglobulin, IgM, and polymeric haptoglobins. The protein concentration of spinalfluid is less than 1% of plasma proteins.Elevation of spinal fluid protein is the most frequently encountered abnormality. The most commoncauses of altered protein concentration are listed below. Increased Protein Decreased Protein Inflammation Water intoxication Tumor Leukemia Demyelinating disorders CSF leakage Subarachnoid hemorrhage Rhinorrhea, otorrhea Traumatic tap Hyperthyroidism Phenothiazine medications PneumoencephalographyInfants have higher protein levels (60-150 mg/dL) due to increased blood brain barrier permeability.Cisternal and ventricular fluids have lower total protein concentration than fluid obtained by lumbarpuncture.CSF protein may be normal or mildly increased in viral meningitis. In most cases of viral meningitis theprotein concentration is < 100 mg/dL. In contrast, acute bacterial meningitis is usually associated with aCSF protein concentration between 100 and 500 mg/dL. CSF protein is almost always high intuberculous meningitis. CSF protein elevation occurs in 20% of patients with primary syphilis and 30-70% with secondary syphilis. Approximately 50% of asymptomatic HIV patients exhibit mildly increasedCSF protein levels.Lumbar disc herniation with sciatica may be associated with increased CSF total protein. CSF proteinconcentration is slightly higher in males with depressive disorders than in women with similar diagnoses.CSF protein is within normal limits in 66% of patients with multiple sclerosis. Protein levels >100 mg/dLare usually not associated with primary neurologic disease.Four groups of drugs have been associated with drug induced aseptic meningitis: nonsteroidal anti-inflammatory drugs (NSAID), antibiotics, intravenous immunoglobulins (IVIG), and OKT3 monoclonalantibody. Most patients present with an abrupt onset of headache, fever, meningismus and alteredmental status. This clinical presentation is not very helpful in differentiating drug induced from infectiousmeningitis. The interval between drug intake and onset of meningitis varies between several minutesand 4 months. Approximately, one third of patients report prior use of the medication in question. Thesingle most frequent underlying disease associated with drug induced meningitis is systemic lupuserythematosis (SLE).The CSF of patients with drug induced meningitis typically shows a leukocytosis, with a median cellcount of 200 cells per uL. Neutrophils predominate in three fourths of the cases and eosinophils areoccasionally noted. The degree of leukocytosis correlates with the severity of fever and inversely withthe time interval from drug exposure. Glucose values are usually within normal limits, but protein levelsare elevated to more than 2 times the upper limit of normal. Laboratory values usually return to normalwithin 5 days after drug withdrawal.Reference range is 16 - 60 mg/dL.Specimen requirement is 1 mL of spinal fluid.
    • Protein Urine QuantitativeUrine protein is a mixture of plasma proteins, renal tubular proteins and those from the lower urinarytract. Very little plasma protein crosses the glomerular capillary membranes in healthy individuals.Traces of albumin and beta globulins may be filtered, but are largely reabsorbed by the proximal tubulecells. Cells of the ascending Loop of Henle may secrete Tamm-Horsfall mucoprotein.Abnormally increased quantities of protein may appear in the urine as a consequence of three majormechanisms. I. Glomerular disease is the most common cause of proteinuria. II. Less commonly, low -molecular weight plasma proteins may spill over into the urine when they are present in high concentrations. Examples include Bence Jones proteins in multiple myeloma, myoglobin in rhabdomyolysis, and hemoglobin in intravascular hemolysis.III. The third mechanism of proteinuria is impaired renal tubular reabsorption of proteins in tubulointerstitial kidney diseases.Quantification of urine protein is useful in categorizing kidney disease and in monitoring treatment. Urineprotein quantitation is usually performed on a 24-hour collection. In healthy adults, urinary proteinexcretion averages about 40 mg per day and the upper limit of normal is 150 mg per day. A urinaryprotein excretion rate of more than 3500 mg per day provides unequivocal evidence of glomerulardisease and defines the nephrotic syndrome. This syndrome is defined as proteinuria that is severeenough to cause hypoalbuminemia and edema, often with hypercholesterolemia. Diabetic nephropathy isthe commonest cause of nephrotic proteinuria. In nondiabetic patients, a few primary glomerulardiseases account for the majority of cases of nephrotic proteinuria. Minimal change disease is the mostfrequent glomerulopathy in children (75%) and membranous nephropathy in adults (40%). Focal andsegmental glomerulosclerosis accounts for 10 - 15% of cases of nephrotic syndrome in children and 15 -25% in adults. Intermediate rates of protein excretion, between 150 and 3000 mg per day, may be seenin any type of kidney disease.Protein concentration in the urine relates to how much protein is filtered and the amount of water in theurine, which varies with hydration status. If a patient filters 200 mg of protein per day, his urine proteinconcentration could be relatively low if he drinks a lot of water or relatively high if he drinks very littlewater. This is why the reference method for quantitating protein in the urine is a 24-hour collection. Bycollecting all the urine over a 24-hour period, then measuring its volume and its protein concentration,one can calculate the total amount of protein excreted during the day. For any given level of proteinexcretion, the urine protein concentration will be low in patients who drink a lot of water, but their 24-hour urine volume will be high; in contrast, the urine protein concentration will be high in patients whodrink very little fluid, but their 24-hour urine volume will be low. It is important to keep in mind that it israre that patients collect 24-hour urines accurately, not to mention that it is an exercise most patientswould rather not undertake.Creatinine is freely filtered through the glomerulus and is not extensively reabsorbed or secreted. Thus,its concentration in the urine is affected by hydration status, in the same way described above forproteinuria. If a patient drinks a lot of water, the urine creatinine concentration will be relatively low; ifhe drinks relatively little water, the urine creatinine concentration will be relatively high. In fact, if onemakes a ratio of urine protein concentration divided by urine creatinine concentration in the samesample, one can eliminate the effect of water entirely. And it has been shown repeatedly that the urineprotein/creatinine ratio is a good surrogate for a 24-hour urine collection.The upper limit of normal for the protein/creatinine ratio is roughly 200 (mg protein/g creatinine), anumber that can be predicted from other reference range data. The typical 24-hour creatinine excretionis roughly 15 mg/kg for women and 20 mg/kg for men, corresponding to roughly 1000 mg/day (1g/day)for women and 1500 mg/day (1.5 g/day) for men. Since the upper limit of normal for 24-hour proteinexcretion can be as high as 150 mg/day, the corresponding ratio would be 150 mg/1 g, or 150. The ratiocan be calculated from any random urine specimen.The following Table illustrates how protein concentrations can be misleading. Even though samples 1and 2 have roughly the same protein concentration, their protein/creatinine ratios are quite different.Sample 2 is very concentrated, as reflected in its high creatinine concentration; once corrected for itsconcentration, the ratio, 100, indicates that the patient is excreting roughly 100 milligrams of proteinper gram of creatinine per day, a value which is normal. In contrast, Sample 1, with about the sameprotein concentration, comes from a patient with a grossly elevated, pathologic, amount of proteinuria;
    • once corrected for its creatinine concentration, the ratio, 800, suggests that the patient is excreting 800milligrams of protein per gram of creatinine. In the same way, Samples 3 and 5 represent a comparableamount of proteinuria, roughly 1600 milligrams per gram of creatinine, but the urine proteinconcentration of Sample 5 is more than four times that of Sample 3. And, finally, Sample 4 has thelargest amount of proteinuria, but its protein concentration is not the highest.Sample Dipstick Protein Dipstick Approximate Urine Total [Creatinine] ProteinNumber Result Protein Protein mg/dL /Creatinine mg/dL mg/dL Ratio1 1+ 30 38 47 8002 1+ 30 46 352 1003 1+ 100 86 55 16004 4+ 300 279 137 20005 4+ 300 358 230 1600In other words, the concentration can be misleading, whether one measures the protein concentrationby dipstick or by spectrophotometry. One must know the protein/creatinine ratio (or an accurate 24hour collection) to draw any conclusions about the degree of proteinuria. There is excellent correlationbetween protein:creatinine ratios in random urine samples and 24 hour collections in healthy individuals,patients with all types of kidney disease, and patients with kidney transplants.Simultaneous reporting of urine protein and creatinine is helpful in assessing the completeness ofcollection and in interpreting low to intermediate protein concentrations in high volume urine samples.Creatinine excretion increases with muscle mass, is lower among women and decreases with age. Menusually excrete 19 to 26 mg of creatinine per kg of body weight daily and women usually excrete 14 to21 mg/kg body weight. Creatinine values < 1g/24 hours for men or < 0.9g/24 hours for women nearlyalways mean that the urine collection was incomplete. Normal urine volume is 0.6 to 2.0 liters per day,but most people produce between 1.0 and 1.5 liters per day.Reference range for urine creatinine is 1 -2 g per 24 hours for men and 0.6 - 1.5 g per 24 hours forwomen.The reference range for 24 hour urine protein is 0-225 mg/24 hours (Vitros 950). The reference rangefor the protein:creatinine ratio 0-150 mg/g.Specimen requirement is a 24-hour urine collection in a container without preservative. Specimen shouldbe refrigerated during and after the collection. Protein: creatinine ratio can be performed on spot urinesamples.
    • Microalbumin Urine Test Test OverviewA microalbumin test evaluates urine for the presence of a protein called albumin. Albumin is normally found in the bloodand filtered by the kidneys. When the kidneys are working properly, albumin is not present in the urine. However,when the kidneys are damaged, small amounts of albumin leak into the urine. This condition is called microalbuminuria.Microalbuminuria is most frequently caused by kidney damage from diabetes. However, many other conditions can leadto kidney damage, such as high blood pressure, heart failure, cirrhosis, or systemic lupus erythematosus (SLE). If earlykidney damage is not treated, larger amounts of albumin and protein may leak into the urine. This condition is calledmacroalbuminuria or proteinuria. When the kidneys spill protein, it can mean serious kidney damage is present. Thiscan lead to chronic kidney disease. A microalbumin urine test can be done on a sample of urine collected randomly(usually after the first time you urinate in the morning), a sample collected over a 24-hour period, or a sample collectedover a specific period of time, such as 4 hours or overnight.Why It Is DoneA microalbumin urine test is done to detect protein (albumin) in the urine, a condition called microalbuminuria, thatmeans your kidneys have been damaged. Early detection may change treatment in an effort to preserve as muchkidney function as possible.How To PrepareNo special preparation is needed before having this test.How It Is DoneFor a random urine test, you will provide a clean-catch midstream urine sample. A morning urine sample provides thebest information about microalbumin levels.Clean-catch midstream one-time urine collectionThis collection method prevents contamination of the sample.  Wash your hands to make sure they are clean before collecting the urine.  If the collection container has a lid, remove it carefully and set it down with the inner surface up. Avoid touching the inside of the container with your fingers.  Clean the area around your genitals. o A man should retract the foreskin, if present, and clean the head of his penis thoroughly with medicated towelettes or swabs. o A woman should spread open the folds of skin around her vagina with one hand, then use her other hand to clean the area around her vagina and urethra thoroughly with medicated towelettes or swabs. She should wipe the area from front to back to avoid contaminating the urethra with bacteria from the anus.  Begin urinating into the toilet or urinal. A woman should continue to hold apart the folds of skin around the vagina while she urinates.  After the urine has flowed for several seconds, place the collection container into the stream and collect about 2 fl oz(59 mL) of this ―midstream‖ urine without interrupting the flow.  Avoid touching the rim of the container to your genital area, and avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.  Finish urinating into the toilet or urinal.  Carefully replace the lid on the container and return it to the lab. If you are collecting the urine at home and cannot get it to the lab within an hour, refrigerate it.A urine sample collected over time, such as over 4 or 24 hours, provides the most accurate results so you may beasked to collect your urine over a specific time period.Timed urine collection (such as 4 hours or 24 hours)  The collection period usually starts in the morning. When you first get up, empty your bladder but do not save this urine. Write down the time that you urinated to mark the beginning of your 24-hour collection period.
    •  Collect all your urine during the allotted time period. Your health professional or lab will usually provide you with a large container that holds about 1 gal(3.8 L) and has a small amount of preservative in it. Urinate into a smaller, clean container and then pour the urine into the large container. Avoid touching the inside of the container with your fingers.  Keep the large container in the refrigerator during the collection period.  Empty your bladder for the final collection at or just before the end of the time period. Add this final sample to the large container and record the time.  Avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.How It FeelsThere is normally no discomfort involved with collecting a 24-hour urine sample.RisksThere are no risks associated with collecting a urine sample.ResultsA microalbumin test evaluates urine for the presence of a protein called albumin. Microalbuminuria is most frequentlycaused by kidney damage from diabetes. Normal results may vary depending on:  The laboratory.  The type (random versus timed) of urine sample collected.  The time of day of the sample.  Whether you are male or female.  Whether you are on bed rest or able to move about normally. 24-hour urine sampleNormal: 30–165 milligrams (mg) of albumin per 24 hours 4-hour timed urine sampleNormal: Less than 30 mg of albumin per 4 hours Random (spot) urine sampleNormal: Less than 30 micrograms of albumin per milligram of creatinineAbnormal resultsYou may need more than one test to find out how well your kidneys are working.  When your kidneys do not work well and leak between 165 and 300 mg of albumin in 24 hours, your doctor may check your urine more often to watch for kidney damage.  If your kidneys leak 300 mg or more of albumin in 24 hours (macroalbuminuria), you may have chronic kidney disease.  If you have 2 or 3 high results in a 3- to 6-month period and you have diabetes, your doctor may find kidney damage (diabetic nephropathy). Even though diabetes is the most common reason for high results, there are many other kidney problems that can cause high results.Pregnant women with diabetes may have their urine checked to watch for high amounts of albumin.
    • What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  High blood sugar levels, urinary tract infections, high blood pressure, heart failure, or a high fever during an infection.  Recent exercise.  Medications, such as aspirin, corticosteroids, and some antibiotics, such as amoxicillin.  Menstrual bleeding and vaginal discharge, which may dilute the urine.What To Think About  The American Diabetes Association recommends a microalbumin urine test for people with: o Type 2 diabetes: first at diagnosis and then annually for diabetic nephropathy. o Type 1 diabetes: annual screening for diabetic nephropathy should begin 5 years after diagnosis.  If a microalbumin urine test shows that kidney damage may be present, a test to evaluate creatinine levels may be done. A blood test for creatinine is done along with a 24-hour creatinine clearance urine test to evaluate kidney function. For more information, see the medical test Creatinine and Creatinine Clearance.  A less precise test, the urine dipstick test, can be used to check for microalbuminuria in a single sample of urine. However, the dipstick test does not accurately detect microalbuminuria and is not recommended as a substitute for the conventional microalbumin urine test.
    • Bilirubin, Total and DirectEighty percent of all bilirubin is derived from the metabolism of hemoglobin released from senescent redblood cells. Hemoglobin released from red blood cells is converted to unconjugated (also called indirect)bilirubin in the reticuloendothelial system. Daily production of unconjugated bilirubin is 250 to 350 mg.Because this bilirubin is water insoluble, it must be transported to the liver bound to albumin. Thecirculating half-life of unconjugated bilirubin is < 5 minutes. In the liver, unconjugated bilirubin istransferred from albumin into hepatocytes where it is conjugated with glucuronic acid. Conjugatedbilirubin (also called direct) is then excreted in the bile and transported to the intestine. Conjugatedbilirubin is essentially absent from the blood of healthy individuals. In the distal ileum and colon,bacteria covert conjugated bilirubin to stercobilinogen. A small fraction is reabsorbed into the portalcirculation and excreted in the urine as urobilinogen. This metabolic pathway accounts for the bilirubindetected in the plasma of healthy individuals.Jaundice is the clinical manifestation of an elevated plasma bilirubin level. It occurs when bilirubinproduction exceeds the livers excretory capacity. This may occur because (1) too much bilirubin is beingproduced, (2) hepatocytes are injured and cannot metabolize or excrete bilirubin, or (3) the biliary tractis obstructed blocking the flow of conjugated bilirubin into the intestine. Examples include hemolyticanemia, acute viral hepatitis, advanced cirrhosis, and obstructive biliary tract disease.If total bilirubin is mildly elevated (usually < 6 mg/dL) and less than 20% is conjugated (direct: totalratio < 0.2), the most likely diagnoses are Gilbert syndrome or hemolysis. Gilbert syndrome affects~5% of the population and causes mild hyperbilirubinemia because of impaired UDP-glucuronyltransferase. Other possibilities include ineffective erythropoiesis, resorption of a largehematoma, pulmonary embolism with infarction, Crigler-Najjar syndrome, neonatal jaundice, andshunts. Because unconjugated bilirubin is water insoluble and bound to albumin, these patients do nothave bilirubinuria. Testing of urine for bilirubin is a simple way to determine if elevated bilirubin isunconjugated or conjugated.Increases in conjugated bilirubin are highly specific for disease of the liver or bile ducts. Hepatocellularinjury or cholestasis is suspected when more than 50% of total bilirubin is conjugated bilirubin (direct:total ratio > 0.4). In common bile duct obstruction due to gallstones, total bilirubin seldom exceeds 15mg/dL and usually remains below 6 mg/dL because obstruction is often incomplete and conjugatedbilirubin is water soluble and excreted by the kidneys. Bilirubin excretion is able to keep pace withproduction. Total bilirubin levels >25 mg/dL usually indicate intrahepatic cholestasis.The following table may help to differentiate the various causes of jaundice. Lab Test Hemolysis Hepatocellular Intrahepatic Extrahepatic cholestasis cholestasis Total bilirubin <6 mg/dL Variable Variable, may be <30 mg/dL >30 mg/dL Direct bilirubin <20% >50% >50% >50% ALT Normal >5 fold increase 2-5 fold increase 2-3 fold increase cholangitis higher ALP Normal 2-3 fold increase 3-5 fold increase 3-5 fold increase PT Normal Prolonged Prolonged Prolonged PT corrected by Not Done No Variable Yes vitamin K
    • In adults, jaundice develops in 70% of cases of acute hepatitis A, 33 - 50% of cases of acute hepatitis Band 20 - 33% of cases of acute hepatitis C. Peak bilirubin is usually < 15 mg/dL in viral hepatitis; only10% of patients have bilirubin >15 mg/dL and only 4% have values >20 mg/dL. Bilirubin peaks a weeklater than ALT and AST and then gradually decreases. In adults with viral hepatitis, bilirubin remainsincreased for 30 +/- 20 days after peak concentrations are reached. In approximately one third of adultswith hepatitis B virus infections, jaundice remains elevated more than 6 weeks. Significantly elevatedbilirubin is uncommon in toxic and ischemic hepatic injury.In the full-term infant, serum bilirubin levels peak at 48 to 72 hours after birth. Kernicterus is apreventable lifelong neurologic syndrome caused by severe & untreated hyperbilirubinemia during theneonatal period. In full term infants, hyperbilirubinemia symptoms include severe jaundice, lethargy andpoor feeding. Kernicterus may result in choreoathetoid cerebral palsy, mental retardation, sersorineuralhearing loss and gaze paresis. Boys are more susceptible than girls to adverse outcomes fromhyperbilirubinemia. Treating hyperbilirubinemia with phototherapy and exchange transfusions preventskernicterus. Kernicterus virtually disappeared in full-term infants until the early 1990s. Increases inbreastfeeding and early hospital discharge after delivery have resulted in a resurgence of kernicterus.Major risk factors for hyperbilirubinemia in full-term newborns include:  Jaundice within first 24 hours after birth  A sibling who was jaundiced as a neonate  ABO or Rh incompatibility  Nonoptimal nursing  G6PD deficiency  Infection  Cephalo-hematoma or bruising  East Asian or Mediterranean descentDuring August 1999, the laboratory introduced a new method that directly measured unconjugated andconjugated bilirubin and calculated total bilirubin by adding these two fractions together. The normalrange for total bilirubin changed from 0.2 - 1.2 mg/dL to 0 - 1.1 mg/dL. The major reason for thisdecrease in total bilirubin was that delta bilirubin was no longer measured. Delta bilirubin is bilirubinbound to albumin, which has a circulating half-life of 15 to 19 days. It is usually increased following aprolonged period of conjugated hyperbilirubinemia and is not clinically important. The normal range fordirect bilirubin remained 0 - 0.3 mg/dL, but many more patients had values of 0 or 0.1 mg/dL thanpreviously.Reference range is 0 to 1.1 mg/dL for total bilirubin and 0.0 to 0.3 mg/dL for direct bilirubin (VitrosAnalyzer using Bu/Bc slide). Bilirubin levels are 33% lower beginning with the second trimester ofpregnancy.Specimen requirement is one green top (heparin tube) or SST tube. The specimen should be protectedfrom light, because unconjugated bilirubin is unstable. One hour of light exposure can cause a 50%decrease.
    • Alkaline phosphataseAlkaline phosphatase refers to a family of enzymes that catalyze hydrolysis of phosphate esters at analkaline pH. ALP is present (in decreasing order of abundance) in placenta, intestine, kidney, bone andliver. In adults, more than 80% of serum ALP activity derives from liver and bone. In late pregnancy,placental ALP is increased. In children and adolescents most serum ALP activity originates in osteoblastsand correlates with the rate of bone growth. The serum half life is seven days.Several caveats must be remembered in interpreting ALP results.  ALP levels should always be measured after fasting because enzyme levels increase as much as 30 U/L after food ingestion. Patients with blood group O and B who are secretors can have increased ALP levels after eating a fatty meal because of the release of intestinal enzyme.  African Americans have 10 to 15% higher ALP serum levels than Caucasians.  In children, ALP is increased up to 3 times the upper limit of normal and in pregnant patients it can be increased up to 2 times normal.  ALP levels may double following bone fracture.  Smokers have 10% higher ALP levels than nonsmokers do.  ALP levels fluctuate approximately 6% from week to week in a healthy individual.ALP is most useful in diagnosing cholestatic liver diseases. Bile duct obstruction results in increasedsynthesis of ALP by bile duct epithelial cells and release of ALP into the serum. Alkaline phosphatase maybe increased even if only a few small bile ducts are obstructed and serum bilirubin is normal. Serum ALPoften exceeds four times the upper limit of normal in extrahepatic and intrahepatic cholestasis. The mostcommon causes of extrahepatic cholestasis are pancreatic cancer, common duct stones and strictures,and primary sclerosing cholangitis. Intrahepatic cholestasis is usually due to primary biliary cirrhosis ordrug reactions (erythromycin, chlorpromazine, estrogens, and methyltestosterone). Patients withprimary sclerosing cholangitis and primary biliary cirrhosis initially have elevated ALP and normalbilirubin levels.When the ALP level is increased disproportionately to the bilirubin level (e.g. a bilirubin < 1.0 mg/dL andALP > 1000 U/L), granulomatous or infiltrative diseases of the liver are likely. Possible diagnoses includesarcoidosis, fungal infections, tuberculosis, and lymphoma. ALP levels are also increased inhyperthyroidism, cardiac failure, lymphoma, and hypernephroma.Lower ALP levels (< 3 times the upper limit of normal) are less specific for cholestatic liver disease andmay be seen with hepatocellular diseases such as acute viral hepatitis, chronic hepatitis, and cirrhosis.However, it is important to remember that incomplete obstruction by gallstones may produce mildlyelevated ALP levels. Intrahepatic cholestasis secondary to anabolic steroids or birth control pills maycause mild increases in ALP. Gamma glutamyltransferase (GGT) can be measured to determine ifelevated ALP levels are of liver origin; increased GGT indicates that ALP is most likely from the liver.Medications that have been reported to increase ALP include; allopurinol, anabolic steroids, captopril,carbamazepine, chlorpromazine, chlorpropamide, diltiazem, erythromycin, estrogens, flutamide, goldsalts, methimazole, methyltestosterone, phenothiazines, phenylbutazone, phenytoin, quinidine,sulfonamides, tolazamide, tolbutamide, trimethoprim-sulfamethoxazole, valproic acid, and verapamil.Sometimes it is useful to look at the relationship of ALP to bilirubin and lactate dehydrogenase (LD)levels. Pathology ALP Bilirubin LD Intra or extrahepatic cholestasis Increased Increased Normal Focal benign cholestasis Increased Normal Normal Focal malignant cholestasis Increased Normal Increased
    • Osteoblastic bone disease can also increase serum ALP. The most common bone disorders associatedwith elevated ALP are; Pagets disease, osteomalacia, hyperparathyroidism, osteogenic sarcoma, andbone metastases.Low alkaline phosphatase levels have been reported in patients with magnesium deficiency,hypothyroidism, malnutrition, hemolytic anemia, Wilsons Disease, post coronary bypass surgery,estrogen replacement therapy, and congenital hypophosphatasia. Blood transfusion causes transientdecreases in ALP, due to chelation of cations by citrate.Reference range in adults is 40 - 125 IU/L (Vitros Analyzer).Specimen requirement is one SST tube of blood. If blood is collected in a citrate or EDTA tube, ALPactivity will be almost totally inhibited due to the chelation of zinc and magnesium, which are necessaryenzyme cofactors.
    • Alkaline Phosphatase Test OverviewAn alkaline phosphatase (ALP) test measures the amount of the enzyme ALP in the blood. ALP is produced primarily inthe liver and in bone. It also is produced by the placenta of a pregnant woman and, to a lesser extent, by the intestinesand kidneys. See an illustration of the liver , the intestines , or the kidneys .Normally, the liver produces more ALP than the other organs or the bones. Some conditions can release large amountsof ALP into the bloodstream. These conditions include rapid bone growth (during puberty), bone disease (osteomalaciaor Pagets disease), or damaged liver cells.The chemical structure of ALP produced by the liver is slightly different from the structure of ALP produced by bone. IfALP levels in the blood are high, further testing may be done to determine the cause of the elevated ALP levels.Why It Is DoneA test for alkaline phosphatase (ALP) is done to:  Diagnose liver disease or monitor its course. Symptoms of liver disease can include jaundice, abdominal pain, nausea, and vomiting. An ALP test may also be used to evaluate the liver when medications are taken that can damage the liver.  Evaluate bone abnormalities (sometimes found on X-rays), such as those resulting from rickets, osteomalacia, bone tumors, or Pagets disease. ALP levels can be used to monitor the effectiveness of treatment for Pagets disease.  Evaluate the cause of a high blood calcium level.How To PrepareYou may be asked to not eat or drink for 10 to 12 hours before the test. ALP levels generally rise after eating, especiallyafter consuming fatty foods.Since many medications can affect the test, be sure to tell your health professional all the medications you take.How It Is DoneThe health professional drawing your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksRisks of a blood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.
    •  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsAn alkaline phosphatase (ALP) test measures the amount of the enzyme ALP in the blood.NormalNormal values may vary from lab to lab. Alkaline phosphatase Adults: 38–126 international units per liter (IU/L)Women in the third trimester of pregnancy have high alkaline phosphatase (ALP) levels because the placenta producesALP. Children usually have much higher ALP levels than adults because rapid bone growth is normal in children.High values  Very high levels of ALP can be caused by liver disorders, such as hepatitis, blockage of the bile ducts (obstructive jaundice), gallstones, cirrhosis, liver cancer, or cancer that has spread (metastasized) to the liver from another location in the body.  High ALP levels can be caused by bone diseases, such as Pagets disease, osteomalacia, rickets, bone tumors, or by overactive parathyroid glands (hyperparathyroidism). Normal healing of a bone fracture can also raise ALP levels.  Heart failure, heart attack, mononucleosis or kidney cancer can raise ALP levels. A serious infection that has spread throughout the body (sepsis) can also raise ALP levels.Low valuesConditions that lead to malnutrition (such as celiac disease) or are caused by a lack of necessary nutrients in the diet(such as scurvy) can result in low ALP levels.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Medications that may damage the liver, such as some antibiotics, birth control pills, long-term aspirin use, and oral diabetes medications.  Pregnancy. Women in the third trimester of pregnancy have high ALP levels because the placenta produces ALP.  Menopause. Postmenopausal women may have higher ALP levels.  Age. Children usually have much higher ALP levels than adults because rapid bone growth is normal in children.  Alcohol use.What To Think About  If the alkaline phosphatase level is high, many health professionals will order a specialized test to help determine the source (liver, bone, or intestine) of the high test result. This test is called alkaline phosphatase isoenzymes, or ALP isoenzymes.  If liver disease is suspected, tests in addition to alkaline phosphatase, such as additional blood tests, ultrasound, or a CT scan, are usually needed to diagnose the problem.  Other tests to monitor liver function, such as alanine aminotransferase, aspartate aminotransferase, and bilirubin, are often done at the same time as an alkaline phosphatase (ALP) test. For more information, see the medical tests Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), and Bilirubin.  Gamma glutamyl transferase (GGT), or gamma glutamyl transpeptidase, may be measured in the blood to distinguish bone alkaline phosphatase (ALP) from liver ALP. High levels of GGT usually are present when
    • the liver is damaged but not present with bone disease. An increased level of GGT may be related toalcohol use or may mean that blocked bile ducts are causing inflammation. The level of GGT also mayincrease with the use of certain medications, such as phenytoin and phenobarbital. In some areas a testthat measures a substance called 5-nucleotidase has replaced the GGT test because it is better atdetecting liver disease.
    • Alkaline Phosphatase (ALP)Alkaline phosphatase refers to a family of enzymes that catalyze hydrolysis of phosphate esters at analkaline pH. ALP is present (in decreasing order of abundance) in placenta, intestine, kidney, bone andliver. In adults, more than 80% of serum ALP activity derives from liver and bone. In late pregnancy,placental ALP is increased. In children and adolescents most serum ALP activity originates in osteoblastsand correlates with the rate of bone growth. The serum half life is seven days.Several caveats must be remembered in interpreting ALP results.  ALP levels should always be measured after fasting because enzyme levels increase as much as 30 U/L after food ingestion. Patients with blood group O and B who are secretors can have increased ALP levels after eating a fatty meal because of the release of intestinal enzyme.  African Americans have 10 to 15% higher ALP serum levels than Caucasians.  In children, ALP is increased up to 3 times the upper limit of normal and in pregnant patients it can be increased up to 2 times normal.  ALP levels may double following bone fracture.  Smokers have 10% higher ALP levels than nonsmokers do.  ALP levels fluctuate approximately 6% from week to week in a healthy individual.ALP is most useful in diagnosing cholestatic liver diseases. Bile duct obstruction results in increasedsynthesis of ALP by bile duct epithelial cells and release of ALP into the serum. Alkaline phosphatase maybe increased even if only a few small bile ducts are obstructed and serum bilirubin is normal. Serum ALPoften exceeds four times the upper limit of normal in extrahepatic and intrahepatic cholestasis. The mostcommon causes of extrahepatic cholestasis are pancreatic cancer, common duct stones and strictures,and primary sclerosing cholangitis. Intrahepatic cholestasis is usually due to primary biliary cirrhosis ordrug reactions (erythromycin, chlorpromazine, estrogens, and methyltestosterone). Patients withprimary sclerosing cholangitis and primary biliary cirrhosis initially have elevated ALP and normalbilirubin levels.When the ALP level is increased disproportionately to the bilirubin level (e.g. a bilirubin < 1.0 mg/dL andALP > 1000 U/L), granulomatous or infiltrative diseases of the liver are likely. Possible diagnoses includesarcoidosis, fungal infections, tuberculosis, and lymphoma. ALP levels are also increased inhyperthyroidism, cardiac failure, lymphoma, and hypernephroma.Lower ALP levels (< 3 times the upper limit of normal) are less specific for cholestatic liver disease andmay be seen with hepatocellular diseases such as acute viral hepatitis, chronic hepatitis, and cirrhosis.However, it is important to remember that incomplete obstruction by gallstones may produce mildlyelevated ALP levels. Intrahepatic cholestasis secondary to anabolic steroids or birth control pills maycause mild increases in ALP. Gamma glutamyltransferase (GGT) can be measured to determine ifelevated ALP levels are of liver origin; increased GGT indicates that ALP is most likely from the liver.Medications that have been reported to increase ALP include; allopurinol, anabolic steroids, captopril,carbamazepine, chlorpromazine, chlorpropamide, diltiazem, erythromycin, estrogens, flutamide, goldsalts, methimazole, methyltestosterone, phenothiazines, phenylbutazone, phenytoin, quinidine,sulfonamides, tolazamide, tolbutamide, trimethoprim-sulfamethoxazole, valproic acid, and verapamil.Sometimes it is useful to look at the relationship of ALP to bilirubin and lactate dehydrogenase (LD)levels. Pathology ALP Bilirubin LD Intra or extrahepatic cholestasis Increased Increased Normal Focal benign cholestasis Increased Normal Normal Focal malignant cholestasis Increased Normal IncreasedOsteoblastic bone disease can also increase serum ALP. The most common bone disorders associatedwith elevated ALP are; Pagets disease, osteomalacia, hyperparathyroidism, osteogenic sarcoma, andbone metastases.
    • Low alkaline phosphatase levels have been reported in patients with magnesium deficiency,hypothyroidism, malnutrition, hemolytic anemia, Wilsons Disease, post coronary bypass surgery,estrogen replacement therapy, and congenital hypophosphatasia. Blood transfusion causes transientdecreases in ALP, due to chelation of cations by citrate.Reference range in adults is 40 - 125 IU/L (Vitros Analyzer).Specimen requirement is one SST tube of blood. If blood is collected in a citrate or EDTA tube, ALPactivity will be almost totally inhibited due to the chelation of zinc and magnesium, which are necessaryenzyme cofactors.
    • Prothrombin Time Test OverviewProthrombin time (PT) is a blood test that measures how long it takes blood to clot. A prothrombin time test can be usedto screen for bleeding abnormalities. PT is also used to monitor treatment with medication that prevents the formation ofblood clots.At least a dozen blood proteins, or blood clotting factors, are needed to clot blood and stop bleeding (coagulation).Prothrombin, or factor II, is one of several clotting factors produced by the liver. Adequate amounts of vitamin K areneeded to produce prothrombin. Prothrombin time is an important coagulation test because it measures the presenceand activity of five different blood clotting factors (factors I, II, V, VII, and X). The prothrombin time is lengthened by:  Low levels of blood proteins (blood clotting factors).  A decrease in activity of any of the factors.  The absence of any of the factors.  The presence of a substance that blocks the activity of any of the factors.An abnormal prothrombin time is often caused by liver disease or injury or by treatment with the medication warfarin(Coumadin), which is used to prevent the formation of blood clots.Another blood clotting test, called partial thromboplastin time (PTT), measures the function of several other clottingfactors. Partial thromboplastin time is often measured along with prothrombin time to evaluate bleeding abnormalities.These two tests together screen for problems with the normal blood clotting process and can detect most blood clottingproblems caused by abnormal amounts of coagulation factors.Why It Is DoneProthrombin time (PT) is measured to:  Determine a possible cause for abnormal bleeding or bruising.  Monitor the effects of the medication warfarin (Coumadin), which is used to prevent blood clots. If the test is done for this purpose, it may be repeated daily at first and then less often when the correct medication dose is determined.  Screen for deficiencies of certain blood clotting factors. The lack of some clotting factors can cause bleeding disorders similar to hemophilia.  Screen for a vitamin K deficiency. Adequate amounts of vitamin K are needed to produce prothrombin.  Monitor liver function. Prothrombin levels are monitored along with other tests (such as aspartate aminotransferase and alanine aminotransferase) to help evaluate liver function. For more information, see the medical tests Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT).How To PrepareMany medications can affect prothrombin time test results. Tell your doctor about all medications you are taking, bothprescription and nonprescription, before having this test. No other special preparations are required before having thistest.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.
    • How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsNormalNormal values may vary from lab to lab.A method of standardizing prothrombin time results, called the international normalized ratio (INR) system, has beendeveloped to compare prothrombin time results among labs using different test methods. Using the INR system,treatment to prevent blood clots (anticoagulant therapy) remains consistent even if a person has the test done atdifferent labs. In some situations, only the INR is reported and the PT is not reported. Prothrombin time (PT) Normal: 10–13 seconds International normalized ratio (INR): 1.0–1.4The warfarin (Coumadin) dosage for people being treated to prevent the formation of blood clots is usually adjusted sothat the prothrombin time is about 1.5 to 2.5 times the normal value (or INR values 2 to 3). Prothrombin times are alsokept at higher levels for people with artificial heart valves, for the same reason.Abnormal values  A long PT can indicate a lack of one or more blood clotting factors (factors I, II, V, VII, or X), a lack of clotting factor activity, a vitamin K deficiency, liver disease, or injury.  A long PT can be caused by treatment with certain medications, such as heparin or warfarin (Coumadin), that are used to prevent the formation of blood clots.  A long PT can be caused by cirrhosis.What Affects the TestFactors that can affect your bloods ability to clot and so affect the PT measured by the test:  Medications that can affect the action of blood-thinners (such as warfarin) and vitamin K, which in turn affects the PT result, including antibiotics, aspirin, cimetidine (Tagamet), barbiturates, birth control pills, hormone replacement therapy (HRT), and vitamin K supplements.  Severe diarrhea or vomiting that causes fluid loss and dehydration, which may increase prothrombin time. If diarrhea is caused by poor absorption of nutrients, vitamins, and minerals from the intestinal tract (malabsorption syndrome), PT may increase because of a vitamin K deficiency.  Foods that contain vitamin K, such as beef liver, pork liver, green tea, broccoli, chickpeas, kale, turnip greens, and soybean products.
    •  Excessive use of alcohol.  Laxatives.  Some herbal products or natural remedies.What To Think About  The U.S. Food and Drug Administration (FDA) has approved a home test for prothrombin time (PT). Discuss the use of a home test with your health professional.  A PT is usually done at the same time of day each time so test results can monitor the dosage of medication used to prevent blood clots.  Another blood clotting test, called partial thromboplastin time (PTT), measures several other clotting factors. PTT is often measured along with PT to evaluate bleeding abnormalities. These two tests together screen for problems with the normal blood clotting process and can detect most blood clotting problems caused by abnormal amounts of coagulation factors. For more information, see the medical test Partial Thromboplastin Time.  Prothrombin levels are monitored along with other tests, such as aspartate aminotransferase and alanine aminotransferase, to help evaluate liver function. For more information, see the medical tests Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT).
    • Prothrombin Time and INR The prothrombin time (PT or protime) is the actual time, measured in seconds, for an anticoagulatedsample of plasma or whole blood to clot after it is added to a thromboplastin reagent. Thromboplastin isa mixture of tissue factor and calcium chloride. The PT assesses the coagulation factors of the extrinsicpathway (factors VII, X and V) and the factors in the common pathway (prothrombinase [a complex ofactivated factor X, activated factor V, and calcium which acts as the substrate for prothrombin],prothrombin, thrombin and fibrinogen). Physicians may request a PT to evaluate a patient:  Investigate a history of a bleeding tendency prior to invasive surgical procedures  Prior to intravascular cardiac surgery or other procedures that interfere with coagulation  Determine the etiology of abnormal bleeding  Assess liver function  Monitor warfarin therapyThe prothrombin time may be prolonged by deficiency of a single or multiple coagulation factors (FactorVII, Factor X, Factor V, Factor II or fibrinogen). The prothrombin time may also be prolonged due to thepresence of a coagulation inhibitor such as a specific factor inhibitor or the lupus anticoagulant.Warfarin acts in the liver by inhibiting the synthesis of vitamin K dependent clotting factors, whichinclude factors II, VII, IX and X, and other proteins essential for the clotting process. Warfarin startsworking in the liver within 24 hours but the maximum effect of a single dose may not be seen for 2-4days. If administered on a daily basis, it usually takes 5-10 days for the warfarin level in the patientsbloodstream to reach a steady state. Due to significant patient variability in response to warfarintherapy, the PT/INR must be closely monitored until a steady state has been reached. Typically,monitoring is performed daily, until several days after the therapeutic range is reached. Warfarin dosagechanges may also be required in response to the PT/INR results. However, until the patient reaches asteady state, PT/INR fluctuations are expected. It may take up to one month for a physician to reach anoptimal therapeutic level of warfarin for an individual patient.Medications (such as antibiotics, birth control pills, estrogens, and other hormones) can also affect theaction of warfarin in the liver, necessitating the evaluation of the possible effect of the added medicationon the PT/INR. Any time a physician changes or adds medication to a patients regimen, the PT/INRshould be checked to ensure that the patient maintains the proper level of anticoagulation. Alcohol,changes in diet, infections, liver disease, and other illnesses also can alter the patients PT/INR. Periodicmonitoring, up to once every month, is necessary as long as the patient remains on anticoagulationtherapy. More frequent routine monitoring may be required in some patients.The American College of Chest Physicians and the National Heart Lung and Blood Institute revised theirrecommendations for intensity of warfarin therapy in 1995. An INR of 2.0 to 3.0 is recommended for allindications except mechanical prosthetic heart valves, for which an INR of 2.5 to 3.5 is recommended.Recommended Therapeutic Ranges for Oral Anticoagulant Therapy Indication INR Prevention of venous thrombosis 2.0 - 3.0 Treatment of venous thrombosis Treatment of pulmonary embolism Prevention of systemic embolism Tissue heart valves Acute myocardial infarction Valvular heart disease Atrial fibrillation Mechanical prosthetic valves 2.5 - 3.5
    • While the PT is a common test for evaluating the coagulation of the patient, differences inthromboplastin reagents have caused problems when comparing results across laboratories. This lack ofcomparability is of special concern for patients who may use more than one laboratory for PT testing.This has been due to varying sensitivities of different thromboplastin reagents used in the PT test. TheWorld Health Organization has recommended a scheme for standardization of oral anticoagulantmonitoring, based on expressing PT results in terms of an International Normalized Ratio (INR).Various thromboplastin reagents have different sensitivities to the warfarin-induced reduction incoagulation factor synthesis. Since 1983 the International Normalized Ratio (INR) has been used tostandardize PT results for patients on warfarin. The INR is a calculation designed to minimize thevariability of PT results due to differences in sensitivity of thromboplastin reagents. With the INR, resultsfrom different laboratories utilizing different methodologies can be compared. Even with the INR,however, significant interlaboratory variations in INR results have been reported.The international sensitivity index (ISI) reflects the sensitivity of the reagent as compared to aninternational standard. The manufacturer of the thromboplastin reagent determines the ISI bycomparing each batch of reagent to a World Health Organization reference plasma and then assigning anISI value to that lot of reagent. Reagent and instrument specific ISIs reduce the variability in INRresults. The INR is calculated from the following formula: ISIINR = (PT patient / PT normal ). PT patient is the patients PT result expressed in seconds.. PT normal is the laboratorys geometric mean value for normal patients expressed in seconds.Each laboratory must determine the normal range for the patients it serves in order to calculate anaccurate INR. To find the normal range, a minimum of 20 unanticoagulated healthy patients evenlydistributed between males and females should be tested. Emergency department or pre-op patientsshould not be used for the normal patient pool, because their blood may contain acute phase reactantsthat are elevated in times of stress and inflammation and can shorten the normal range. Testing shouldbe completed over a period of several days to include intra-lab variabilities.The INR result is the patients PT result in seconds divided by the geometric mean of PT resultof the laboratorys normal patients, as calculated by each laboratory. The geometric mean is atype of average that is different from the simple arithmetic average. It is calculated by multiplying allthe PT results together (in this case, the 20 normal PT results) raised to the reciprocal of the number ofresults (in this case, 1/20). The geometric mean is used to avoid bias that may be caused by theinclusion of extremely high or low values. A calculator or software program is necessary to calculategeometric mean.Because of the exponential nature of the equation for calculating the INR result, a lower ISI yields amore accurate result. The College of American Pathologists (CAP) Conference on Laboratory Monitoringof Anticoagulant Therapy held in 1998 recommended that an ISI between 0.9 and 1.7 be used, withthe desired range being at the lower range of this scale. The following table illustrates the effect that theISI can exert on the INR result. Patient PT result ISI Calculated INR result 33.0 1.00 3.0 22.9 1.5 3.0 19.0 2.00 3.0INR calculations are intended to yield identical INR results when a single specimen is tested by twolaboratories; one using a more sensitive thromboplastin (yielding a higher PT result) and the other usinga less sensitive thromboplastin (yielding a lower PT result).It was previously believed that INR precision would be improved by using more sensitivethromboplastins (with lower ISI values). This has been shown to be incorrect. One intrinsic source oferror in INR reporting is the fact that any imprecision in the PT measurement is amplified exponentially
    • when the INR is calculated. This imprecision is greater for higher PT and INR values. Other problemscontributing to lack of INR reproducibility include differences in sample collection or handling, andinherent biological variation in individuals. All of these limitations in the INR system are illustrated by astudy in which parallel INR determinations were performed at three different hospitals within a singlecommunity, using split plasma samples from patients on long-term warfarin therapy. When the patientINRs were classified as therapeutic, sub- or supratherapeutic, interlaboratory discrepancies wereobserved in 30% of paired samples, with the majority of discrepancies occurring with INR values greaterthan 3.0.Laboratories must do extensive comparison studies before switching to a new lot of PT reagent orchanging methodology to confirm accuracy of the assigned ISI value. The CAP Coagulation ResourceCommittee has published a checklist to assist laboratories with prevention of problems with the INRcalculation.  Has an appropriate reference range for your current reagent/instrument been identified?  Is the geometric mean of this reference range being used in the calculation?  Is the correct ISI being used in the calculation? The ISI varies not only with the lot of reagent but also with the instrument being used.  When performing the calculation, the values for the patient PT and the PT reference range mean include one decimal place (e.g. 12.0) and ISI includes two decimal places (e.g.1.05). In each case, three significant digits are used. The INR should then be rounded and reported to one decimal place (e.g. 2.5; two significant digits).  How is the calculation being performed? Manually? By the instrument? By the LIS? The calculation should only be performed by one of these methods. Having more than one method in place increases the maintenance efforts and increases the risk of miscalculation.  If a manual method of calculation is used, how do you minimize errors?  Is the calculation tested periodically to assure that the correct INR is being produced? In particular, this calculation must be tested immediately after changing any component of the formula (ISI or the geometric mean of the reference range). Actual patient reports should be periodically reviewed to assure the appropriately calculated result is being reported.  Are specimens collected into 3.2% citrate-not 3.8%? Published reports have documented that INR results differ between the two citrate concentrations. Some laboratories continue to use 3.8% citrate despite international efforts to standardize on 3.2%.One important practical issue related to the imprecision of the INR is the question of warfarin doseadjustment. Random variation of INR values may occur in a patient on stable oral anticoagulant dosage,as a result of both biological and analytic variation. This total random variation has been estimated at~10%. This data has been used to evaluate whether a change in the INR represents clinicallyinsignificant random variation, or a clinically relevant change requiring warfarin dose adjustment. It hasbeen calculated that in a patient on fixed dose and steady state warfarin, a change in the INR issignificant only if it is a change (increase or decrease) of greater than 0.28 times the previous INRvalue. This is detailed in the accompanying table. Significant change in Range of Previous INR would be greater acceptable INR INR than variation 2.0 0.6 1.4 - 2.6 2.5 0.7 1.8 - 3.2 3.0 0.8 2.2 - 3.8 3.5 1.0 2.5 - 4.5In summary, the INR reporting system is a major improvement over PT values for standardization oforal anticoagulant monitoring, however clinicians should bear in mind that the system is not problem-free, and that apparent discrepancies may arise between different laboratories, and over time within asingle patient.A sensitive thromboplastin reagent for measuring prothrombin times (PTs) is associated with improvedprecision in PT testing, as well as a wider therapeutic PT range, resulting in more reliable monitoring of
    • oral anticoagulant therapy, and facilitation of dose adjustment.Preanalytic VariablesThere are many variables that can affect the PT/INR result outcome. In fact, preanalytical variablesaccount for up to 64% of all errors in PT/INR testing. One of the most important factors is theanticoagulant used in drawing the blood specimen. The World Health Organization and NCCLS guidelinesrecommend the use of 3.2% buffered citrate. The evacuated tube must be completely filled (at least90% full) to maintain the proper anticoagulant-to-blood ratio. It is best to avoid traumatic venipuncturesto minimize the release of tissue factor, which can initiate coagulation. Although not critical forcoagulation specimens, it is always good practice to release the tourniquet as soon as possible. Theblood sample must be centrifuged for sufficient time (10 minutes) to create platelet-poor plasma as thepresence of platelets in the specimen can shorten clotting times. Specimens for PT testing may be storedat room temperature and will yield valid results for specimens stored up to 24 hours, provided that thecollection tube remains unopened. If testing cannot be performed within this time period, the platelet-poor plasma should be frozen.Reference range is 11.4-14.2 seconds. Critical values are an INR >2.0 in patients who are notanticoagulated and an INR of 4.0 if the patient is anticoagulated.Specimen requirement is one light blue top (sodium citrate) tube of blood drawn after a 5 mL red topdiscard tube.
    • PTT or Plasma Thromboplastin TimeThe activated partial thromboplastin time (APTT) is a global plasma coagulation test affected byabnormalities in the intrinsic (factors XII, XI, VIII, IX, prekallikrein, and high molecular weightkininogen) and common portions of the classic coagulation pathway. The concept of separate intrinsicand extrinsic pathways of coagulation is useful for understanding and diagnosing blood coagulationabnormalities in vitro, however it should be appreciated that in vivo there are interactions between thetwo pathways outside of the classic scheme. The APTT will generally be prolonged when a clotting factorlevel is less than 30-40%. Since the normal range for most clotting factors is 50-150% (and 70-130%for factor XI), a normal APTT does not rule out the possibility of a mild factor deficiency.The test is performed by adding PTT reagent to plasma and measuring the time for clot formation. PTTreagent contains a particulate activator (kaolin, celite, silica or elagic acid) and a partial thromboplastin,which is phospholipid. The activator initiates the contact system. Then, the remaining steps of theintrinsic pathway take place in the presence of phospholipid.There are 6 causes of a prolonged APTT (with PT normal or slightly prolonged):  Pre-analytical errors  Heparin  Coagulation factor deficiency associated with risk of hemorrhage  Coagulation factor deficiency with no risk of hemorrhage  Lupus anticoagulant  Specific coagulation factor inhibitorIn the investigation of a prolonged APTT, pre-analytical errors should be ruled out first. The mostcommon pre-analytical cause of a prolonged APTT is contamination with heparin in a sample drawn froman arterial or central line (APTT will often be >200 seconds). The APTT will be affected by an alteredplasma to citrate ratio in blue top collection tubes, which may be seen with a high hematocrit (>55%),or a sample with a short or long draw. Other pre-analytical problems include dilution of a sample drawnabove an IV, formation of clots in a sample due to inadequate mixing, delay in transport or processing ofa sample (>4 hours), and inadequate centrifugation.The APTT is used most frequently to monitor anticoagulation with unfractionated heparin. Eachlaboratory should set its own APTT therapeutic range for heparin, corresponding to a heparin level of0.3-0.7 U/mL. In Saint Lukes Regional Laboratories this therapeutic range is currently 60-100 seconds.In cases of apparent heparin resistance where the APTT does not rise appropriately, a heparin assay isindicated to determine if a therapeutic amount of heparin is present. Low molecular weight heparin(LMWH) will cause only a mild prolongation of the APTT; if monitoring of LMWH is required, a specificLMWH assay is used. The APTT is prolonged by direct thrombin inhibitors such as Argatroban andlepirudin, and is used to monitor anticoagulation with these drugs. Less frequent causes includehydoxyethyl starch, hematin, Suramin and pegylated drugs.Hereditary coagulation factor deficiencies which selectively prolong the APTT and are associated with ableeding tendency include factors VIII, IX and XI. The common acquired coagulopathies such as liverdysfunction and DIC may cause prolongation of the APTT, however the PT will also be prolonged in thesedisorders, due to multiple clotting factor deficiencies. Hereditary coagulation factor deficiencies whichselectively prolong the APTT but are not associated with a risk of hemorrhage include deficiencies offactor XII, prekallikrein and high molecular weight kininogen.Lupus anticoagulants are acquired inhibitors directed against phospholipid-binding proteins, interfere invitro with phospholipid-dependent coagulation tests, and are a common cause of APTT prolongation. Invivo, lupus anticoagulants do not interfere with coagulation factor complex formation on the plateletphospholipid surface, and are thus not usually associated with a bleeding tendency.Approximately 15% of patients with severe factor VIII or IX deficiency develop alloantibodies (inhibitors)to transfused factor concentrate. Autoantibodies against clotting factors may also arise spontaneously,or associated with various diseases and drugs, most commonly directed against factor VIII. Theinhibitor-factor complexes are rapidly cleared, resulting in factor deficiency and a severe bleedingtendency.
    • An approach to the evaluation of a prolonged APTT is outlined in the following algorithm.The reference range for PTT is 21-34 seconds.Plasma specimens for PTT must be tested within 4 hours of collection. If this is not possible, the plasmacan be stored frozen. Because platelet contamination of plasma can alter the PTT result, specimensshould be centrifuged and the plasma separated promptly.Does a Shortened APTT have any Clinical Significance?In the realm of coagulation testing, much attention has been paid to the investigation and clinicalsignificance of a prolonged APTT. Little if any attention has been given to the significance of a shortenedAPTT. There is evidence that increased levels of several coagulation factors (factors VIII, IX, XI, II, andfibrinogen) are independent risk factors for venous thromboembolism (VTE). These factors participate inthe coagulation cascade in the intrinsic pathway (factors VIII, IX and XI) and common pathway (factor IIand fibrinogen). A shortening of the APTT should reflect increased levels of these factors. Based on thishypothesis, a recent study (Blood, 2004;104: 3631-34) investigated the association between ashortened APTT and the risk of venous thromboembolism (VTE).A case control study was carried out to compare the APTT values in 605 patients referred forthrombophilia testing after an episode of documented VTE and 1290 healthy controls. The APTT wasperformed at least 3 months (range 3-79 months) following the thrombotic event, and patients wereexcluded if they were on anticoagulant drugs, or if they had other conditions potentially affecting theAPTT (e.g. lupus anticoagulant, pregnancy). Thrombophilia testing was also performed including factor VLeiden, prothrombin gene mutation, antithrombin, protein C and protein S. The APTT values in patientsand controls were expressed as a ratio of the test APTT to a reference (pooled normal plasma) APTT.The median value for the test/reference APTT ratio was 0.97 in patients and 1.00 in controls - a smalldifference that was nonetheless statistically significant. The odds ratio for VTE was 2.4-fold increased inpatients with an APTT ratio less than 0.87. In Saint Lukes Regional Laboratories this value wouldcorrespond to an APTT of less than 25 sec (our APTT normal range is 22-32 sec). The relative risk of VTEincreased as the APTT ratio decreased - the odds ratio for VTE was 4.6 for an APTT ratio of equal to orless than 0.8 (corresponding APTT 23 sec). When patients with the shortest APTTs were compared with
    • those with the longest APTTs, the relative risk of VTE was increased 5-fold. These odds ratios have beenadjusted for age, sex, and the presence of inherited thrombophilic disorders. Factor VIII assays wereperformed on a subgroup of the samples. When the results were adjusted for factor VIII levels, theincreased relative risk of VTE remained significant, indicating that high levels of factor VIII were not theonly determinants of the shortened APTTs.In summary, this study suggests that a shortened APTT may be associated with an increased risk ofVTE, independent of inherited thrombophilic defects. A direct causal effect of the hypercoagulabilityreflected by the shortened APTT cannot be established. If the results of this study are confirmed andextended by others using a variety of different reagents, the APTT may prove to be a simple, cheap anduseful screening test for high coagulation factor levels in the investigation of thrombophilia.
    • Partial Thromboplastin Time Test OverviewPartial thromboplastin time (PTT) is a blood test that measures the time it takes blood to clot. A PTT test can be used toscreen for bleeding abnormalities.At least a dozen blood proteins, or blood factors, are needed to clot blood and stop bleeding (coagulation). The partialthromboplastin time is an important coagulation test because the time it takes your blood to clot may be affected by:  Medications you take to prevent the formation of blood clots (blood-thinning medication), such as heparin. The activated partial thromboplastin time (APTT) test is used after taking blood-thinners to determine the most effective dosage of medication that prevents blood clots.  Low levels of blood proteins (blood clotting factors).  A decrease in activity of any of the factors.  The absence of any of the factors.  The presence of a substance that blocks the activity of any of the factors.Another blood clotting test, called prothrombin time (PT), measures the function of several other clotting factors.Prothrombin time is often measured along with partial thromboplastin time to evaluate bleeding abnormalities. Thesetwo tests together screen for problems with the normal blood clotting process and can detect most blood clottingproblems caused by abnormal amounts of or abnormal function of coagulation factors.Why It Is DonePartial thromboplastin time (PTT) is done to:  Determine a possible cause of abnormal bleeding or bruising.  Screen for deficiencies of certain blood clotting factors. The lack of some clotting factors can cause bleeding disorders such as hemophilia.  Screen for conditions that cause abnormal clotting or blood clot formation. Conditions such as antiphospholipid antibody syndrome or lupus anticoagulant syndrome develop when the immune system produces antibodies that attack certain blood clotting factors, causing the blood to clot easily in veins and arteries.  Screen blood clotting time before a surgery.The activated partial thromboplastin time (APTT) test is used to determine the most effective dosage of somemedications, such as heparin, that prevent blood clots. If the test is done for this purpose, an APTT may initially berepeated every few hours. When the correct dosage is found, the frequency of testing is decreased.How To PrepareMany medications can affect PTT test results. Tell your health professional about all medications you are taking, bothprescription and nonprescription, before having this test. No other special preparations are required before having thistest.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain
    • (or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsPartial thromboplastin time (PTT) is a blood test that measures the time it takes blood to clot.NormalNormal values may vary from lab to lab. Partial thromboplastin time (PTT): 30–45 seconds Activated partial thromboplastin time (APTT): 25–39 secondsThe heparin dosage for people being treated to prevent the formation of blood clots is usually adjusted so that the PTTor APTT is about 1.5 to 2.5 times the normal value.Abnormal values  A longer-than-normal PTT or APTT can indicate a deficiency or abnormality of one of the blood clotting factors or another substance needed to clot blood. A deficiency of one or more of these factors results in a bleeding disorder (such as hemophilia or von Willebrands disease).  A long PTT or APTT can be caused by liver disease, kidney disease (such as nephrotic syndrome), or treatment with medications such as heparin or warfarin (Coumadin) that are used to prevent the formation of blood clots.  A long PTT may be caused by conditions such as antiphospholipid antibody syndrome and lupus anticoagulant syndrome that can cause abnormal clotting or blood clot formation. These syndromes are a complication of lupus in which the immune system produces antibodies that attack certain blood clotting factors, causing the blood to clot easily in veins and arteries.  PTT can be increased when aspirin is used during heparin therapy, so the PTT value needs to be closely monitored.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Some herbal products or natural remedies.  Some medications, such as antihistamines.What To Think About  The partial thromboplastin time (PTT) and activated partial thromboplastin time (APTT) may be normal in people who have inherited bleeding disorders with only mild symptoms.  The APTT is used to monitor treatment of people who are receiving heparin or other blood-thinning medication to prevent the formation of blood clots.
    •  Sometimes people who are receiving heparin have an increased APTT because of other substances in their blood and not because of blood-thinning treatment. A test called the heparin neutralization assay may be done to determine whether this is the case. Another blood clotting test, called prothrombin time (PT), measures the function of several other clotting factors. Prothrombin time is often measured along with partial thromboplastin time to evaluate bleeding abnormalities. For more information, see the medical test Prothrombin Time (PT).
    • Partial Thromboplastin Time, Activated (APTT)The activated partial thromboplastin time (APTT) is a measure of the integrity of the intrinsic andcommon pathways of the coagulation cascade. The APTT is the time, in seconds, for patient plasma toclot after the addition of an intrinsic pathway activator, phospholipid and calcium. The APTT reagent iscalled a partial thromboplastin because tissue factor is not included with the phospholipid as it is withthe protime (PT) reagent. The activator initiates the contact system. Then, the remaining steps of theintrinsic pathway take place in the presence of phospholipid. Reference range varies from laboratory tolaboratory, but is usually in the range of 22 - 34 seconds.The concept of separate intrinsic and extrinsic pathways of coagulation is useful for understanding anddiagnosing blood coagulation abnormalities in vitro, however it should be appreciated that in vivo thereare multiple interactions between the two pathways. The APTT will generally be prolonged when aclotting factor level is less than 30-40%. Since the normal range for most clotting factors is 50-150%, anormal APTT does not rule out the possibility of a mild factor deficiency.There are 6 causes of a prolonged APTT in the presence of a normal or slightly prolonged PT:  Pre-analytical errors  Heparin  Lupus anticoagulant  Coagulation factor deficiency associated with risk of hemorrhage  Coagulation factor deficiency with no risk of hemorrhage  Specific coagulation factor inhibitorIn the investigation of a prolonged APTT, pre-analytical errors should be ruled out first. The mostcommon pre-analytical cause of a prolonged APTT is contamination with heparin in a sample drawn froman arterial or central line. The APTT is also affected by an altered plasma to citrate ratio in blue topcollection tubes, which may be seen with a high hematocrit (>55%), or a sample with a short or longdraw. Other pre-analytical problems include dilution of a sample drawn above an IV, clot formation dueto inadequate mixing, and transport or processing delays >4 hours.Therapeutic IV administration of unfractionated heparin is the most common cause of a prolonged APTTin inpatients. Subcutaneous administration of low molecular weight heparin seldom prolongs the APTTmore than 40 seconds.Lupus anticoagulants are acquired inhibitors directed against phospholipid-binding proteins and are acommon cause of APTT prolongation. In vivo, lupus anticoagulants do not interfere with coagulationfactor complex formation on the platelet surface, and are not usually associated with a bleedingtendency.Hereditary coagulation factor deficiencies which selectively prolong the APTT and are associated with ableeding tendency include factors VIII, IX and XI. Hereditary coagulation factor deficiencies whichselectively prolong the APTT but are not associated with a risk of hemorrhage include factor XII,prekallikrein and high molecular weight kininogen (HMWK).Approximately 15% of patients with severe factor VIII or IX deficiency develop alloantibodies (inhibitors)to transfused factor concentrate. Autoantibodies against clotting factors may also arise spontaneously,or associated with various diseases and drugs, most commonly directed against factor VIII. Theinhibitor-factor complexes are rapidly cleared, resulting in factor deficiency and a severe bleedingtendency.The common acquired coagulopathies such as liver disease, moderate to severe vitamin K deficiency,DIC and massive transfusion may cause prolongation of the APTT; however the PT will also be prolongedin these disorders, due to multiple clotting factor deficiencies.A mixing study is used to differentiate between a coagulation factor deficiency and the presence of aninhibitor. It is usually performed by mixing equal volumes of patient plasma and normal pooled plasmaand then repeating the APTT. The basic principle is that the normal plasma contributes a sufficientamount of clotting factor to correct for a factor deficiency. A mixing study that corrects the APTT ischaracteristic of a coagulation factor, whereas one that does not indicates a factor inhibitor. Mixingstudies on mildly prolonged APTTs (< 5 seconds above upper limit of normal) are confusing and difficultto interpret.
    • Inhibitors are classified into 3 general categories:  Medications such as heparin and direct thrombin inhibitors (lepirudin, argatroban)  Nonspecific inhibitors such as lupus anticoagulants  Specific coagulation factor inhibitors such as a factor VIII inhibitorHeparin and direct thrombin inhibitors can be ruled by reviewing the clinical history and medication list.However, this review cannot detect a sample that is contaminated by heparin at the time of collection.Heparin can be confirmed by performing a heparin anti-Factor Xa assay.In practice, two types of mixing studies are actually performed: immediate and incubated. In theimmediate mix, the APTT is performed immediately after mixing patient and normal plasma. In theincubated mix, the APTT is performed after incubating the mixture for one hour. The incubated mix isnot necessary if the immediate mix shows evidence of a fast acting inhibitor such as a lupusanticoagulant. However, the incubated mixing study is necessary to distinguish between a factordeficiency and a time dependent inhibitor such as a factor VIII inhibitor.Two assays are commonly used to confirm the presence of a lupus anticoagulant. The hexagonal phasephospholipid test consists of adding phospholipid to the APTT. The second assay is based on addingphospholipid to the dilute Russell Viper venom test. Shortening of the clotting time in either or both ofthese assays confirms that inhibition of the APTT is phospholipid dependent.In the realm of coagulation testing, much attention has been paid to the investigation and clinicalsignificance of a prolonged APTT. Little if any attention has been given to the significance of a shortenedAPTT. There is evidence that increased levels of several coagulation factors (factors VIII, IX, XI, II, andfibrinogen) are independent risk factors for venous thromboembolism (VTE). These factors participate inthe coagulation cascade in the intrinsic pathway (factors VIII, IX and XI) and common pathway (factor IIand fibrinogen). A study published in 2004 demonstrated an association between a shortened APTT andincreased risk of VTE, independent of inherited thrombophilic defects (Blood, 2004;104: 3631-34).
    • Specimen requirement is one light blue top (sodium citrate) tube. To avoid tissue fluid contamination, a5-mL red top discard tube should be drawn first. Specimen should be delivered to the laboratory within 4hours. If delivery will be delayed, plasma should be separated and frozen. Also see Coagulation Screen.
    • Liver tests for hepatitis C Exam OverviewThese blood tests are used to determine whether your liver is damaged or inflamed. Although these tests help yourdoctor evaluate how well your liver is working, they do not confirm hepatitis C.Tests that assess liver functionYour doctor may do tests to measure your levels of certain chemicals produced by the liver. These tests can help yourdoctor know how well your liver is working. Tests may measure:  Bilirubin.  Albumin.  Prothrombin time (a measure of blood clotting). It may also be called International Normalized Ratio (INR).Tests for inflammation of the liver (liver enzyme studies)If you have increased levels of the following, your liver may be damaged.  Alanine aminotransferase (ALT or SGPT)  Aspartate aminotransferase (AST or SGOT)An increased level of alkaline phosphatase (AP) may indicate blockage of bile ducts.Why It Is DoneLiver tests are done when a medical history or physical exam suggests that something may be wrong with your liver.These tests can also diagnose long-term (chronic) infection. Hepatitis C infection is considered chronic when liverenzymes remain elevated for more than 6 months.If you are being treated with antiviral therapy, you may have liver tests from time to time to see whether treatment isworking.ResultsFindings of liver tests may include the following.NormalAll levels are within the normal range.AbnormalAbnormal liver function tests may indicate that your liver is inflamed or is not working normally. This can be a sign thatyou have a viral infection.What To Think AboutElevated liver enzymes can be caused by many things other than hepatitis C, such as obesity, hepatitis B, autoimmunehepatitis, certain medicines, or long-term alcohol use. Therefore, you will need other tests (such as a hepatitis Cantibody blood test or a liver biopsy) to confirm a diagnosis of hepatitis C.People with chronic hepatitis C have abnormal liver enzyme levels most of the time. However, the levels can fluctuatebetween normal and abnormal throughout the course of the disease.Liver tests can be used to help you and your doctor develop a treatment plan. Indications for treatment may include:
    •  Liver enzyme levels that remain above normal for more than 6 months, which is evidence of chronic infection. Detectable levels of hepatitis C virus in your bloodstream (positive hepatitis C RNA test). This is a sign of an active infection. Evidence of significant liver damage. This is detected with a liver biopsy.
    • Liver tests for infectious mononucleosis Exam OverviewLiver tests are used to study liver function and to determine if the liver is damaged or inflamed. These tests are done ona blood sample.Indicators of liver function  Bilirubin  Albumin  Prothrombin timeIndicators of liver damage or inflammation (liver enzyme studies)  Alanine aminotransferase (ALT)  Aspartate aminotransferase (AST)  Alkaline phosphatase  Lactate dehydrogenase (LDH) (in Cardiac Enzyme Studies)Why It Is DoneThese tests are done when your medical history and the findings of a physical examination suggest that you have acondition (such as a viral infection) that might have affected the liver.ResultsFindings of liver tests may include the following.NormalAll levels are within normal range.AbnormalAbnormal liver function tests indicate that the liver is inflamed or is not functioning normally.Elevated enzyme levels indicate liver inflammation (hepatitis), which may be a clue that a viral infection is present.What To Think AboutElevated liver enzymes may be due to many causes other than mono, including other viral infections (such as hepatitisB); severe bacterial infection; heart disease; heart attack; bone, muscle, and joint injuries; and certain cancers.Therefore, liver function tests alone are not a reliable way to confirm a diagnosis of mono.If your liver enzymes are elevated because of mono, they will return to normal without treatment after the illness goesaway.
    • Hepatitis A Virus Test Test OverviewHepatitis A virus tests detect substances in the blood that indicate a hepatitis infection is active or has occurred in thepast. The test detects proteins (antibodies) made by the body in response to the virus that causes hepatitis. It isimportant to identify the type of hepatitis virus causing infection so that its spread can be prevented and the propertreatment can be started immediately.Hepatitis A virus (HAV) testingHAV infection is spread through food or water that has been contaminated by the feces (stool) of an infected person.  IgM anti-HAV antibodies indicate a recent infection with hepatitis A virus. IgM anti-HAV antibodies generally can be detected in the blood as early as 2 weeks after the initial HAV infection. These antibodies disappear from the blood 3 to 12 months after the infection.  IgG anti-HAV antibodies mean that you have had a hepatitis A viral infection. About 8 to 12 weeks after the initial infection with hepatitis A virus, IgG anti-HAV antibodies appear and remain in the blood for lifelong protection against HAV.Hepatitis A vaccine is available to prevent an HAV infection. If you have had this vaccine and you have anti-HAVantibodies, this means the vaccination was effective.Why It Is DoneHepatitis virus testing is done to:  Diagnose and identify the type of hepatitis virus causing the infection. Other tests that indicate how well the liver is functioning are usually done to support a diagnosis of hepatitis. (See the What to Think About section.)  Screen people (such as doctors, dentists, and nurses) who have an increased risk of getting or spreading a viral hepatitis infection.  Screen potential blood donors and donor organs to prevent the spread of hepatitis.  Determine whether a person has developed antibodies after receiving vaccinations for hepatitis A. The presence of antibodies to hepatitis A virus (anti-HAV) indicates the vaccinations were effective.  To further evaluate abnormal liver function tests.How To PrepareNo special preparation is needed before having hepatitis virus testing.Tell your health professional whether you are taking any herbs or natural substances, because some of these productsmay affect your test results.Talk to your health professional about any concerns you have regarding the need for the test, its risks, or how it will bedone. To help you understand the importance of this test, fill out the medical test information form (What is a PDFdocument?).How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It Feels
    • You may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsHepatitis A virus (HAV) tests detect substances in the blood that indicate a hepatitis infection is active or has occurred inthe past. The test detects proteins (antibodies) made by the body in response to the virus that causes hepatitis. Normalresults of hepatitis virus testing are called negative. This means that no antibodies of a hepatitis virus were found.Abnormal (positive) Hepatitis A and E virus tests Hepatitis A virus (HAV) antibodies are detected. Additional tests may be needed to determine whether you have a present, active infection or a past, resolved infection.  Hepatitis A IgM antibodies indicate an active infection. IgM antibodies generally can be detected Hepatitis A in the blood as early as 2 weeks after you become infected with HAV, when symptoms of hepatitis (HAV) A are present, and for a few months after symptoms have gone away.  Only HAV IgG antibodies indicate a past, resolved infection or that you have been immunized against hepatitis A. This means that you are protected against the infection for life.What Affects the TestHerbs and other natural products may interfere with the accuracy of the results.What To Think About  Hepatitis A can be prevented by vaccination. The presence of antibodies to the hepatitis A virus can also indicate that you have developed immunity to the infection after being vaccinated.  Hepatitis antibodies can take weeks or months to develop, so a person infected with hepatitis may initially test negative if testing is done early in the infection.  Other tests that indicate how well the liver is functioning are usually done to support a diagnosis of hepatitis. These tests can include measuring levels of bilirubin, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase. For more information, see the medical tests Bilirubin, Alkaline Phosphatase, Alanine Aminotransferase (ALT), and Aspartate Aminotransferase (AST).  In many states, some types of hepatitis infections must be reported to the local health department. The health department can then issue a warning to other people who may have been infected with the hepatitis virus, such as those who ate food served by a person infected with hepatitis A.  Hepatitis A virus does not cause chronic illness, so there is no need for follow-up testing once the infection resolves.  HEV infection is spread through food or water that has been contaminated by the feces (stool) of an infected person. Like hepatitis A, hepatitis E causes a sudden (acute) infection that does not develop into a chronic infection. It is rare in North America. Tests for hepatitis E that detect HEV antibodies (anti-HEV), antigens, or genetic material (RNA) are available only in research laboratories.
    • Hepatitis A Antibody IgG and IgM Hepatitis A vaccine is available to prevent hepatitis A infection in persons at high risk for the disease. Approximately 50% of the adult population have antibodies to hepatitis A virus due to previous infection. IgG antibody to HAV usually persists for lifetime, conferring immunity to further hepatitis A infections. Because of the high cost of the vaccine, some physicians prefer to test for hepatitis A antibody to assess the need for vaccination. The hepatitis A IgM antibody test, which is part of the acute hepatitis profile, is not useful in determining previous viral exposure. A test for total hepatitis antibody (IgG and IgM) should be ordered. Ifthis test is positive and the person does not have any signs or symptoms of acute hepatitis, it can be assumed that they have protective levels of hepatitis IgG antibody. Results are reported as positive or negative. The reference value is negative. Specimen requirement is one SST tube of blood
    • Hepatitis A Antibody IgMThe hepatitis A virus (HAV) is a small, 27 nm RNA virus. It is transmitted primarily by the fecal-oral route, and is found more commonly in situations where unsanitary conditions and/or close contact among individualsexist. Contaminated food and water are frequent means of transmission. Although ~70% of children aged < 6 years with HAV infection are asymptomatic, older children and adults usually have symptoms and 70% are jaundiced.The incubation period is short, averaging 25 days and ranging from 15-45 days. Serum IgM antibody to the hepatitis A virus (anti-HAV) appears at about four weeks after initial infection and usually persists for 2-6months as the initial phase of the immune response. Subsequently, only IgG antibodies are detected. Serum IgG antibody to HAV generally persists for lifetime, conferring immunity to further type A infection. HAV is typically self-limited and does not lead to chronic liver disease or to a persistent carrier state.Measurement of the HAV IgM antibody is the preferred diagnostic test for acute infection. A positive IgM anti- HAV test result in a person without symptoms of hepatitis A might indicate:  Asymptomatic acute HAV infection  Previous hepatitis A infection with prolonged presence of IgM anti-HAV  False positive test result A minority of patients have detectable IgM anti-HAV for as long as 30 months after onset of illness. False positive results are more likely to occur when patients are tested who do not have symptoms of acutehepatitis. False positive results also are more likely to be female and older. A false positive result is likely if a patient has a positive IgM anti-HAV and a negative total (IgG and IgM) anti-HAV result. Results are reported as positive or negative. Reference value is negative. Specimen requirement is one SST tube of blood.
    • Hepatitis B Virus Test Test OverviewHepatitis B virus tests look for substances in the blood that show a hepatitis infection is active, ongoing (chronic), or hasoccurred in the past. The tests look for antigens, antibodies, or genetic material (DNA or RNA) of the viruses that causehepatitis. It is important to identify the type of hepatitis virus causing infection to prevent its spread and begin the propertreatment immediately.Hepatitis B virus (HBV) testingHBV is transmitted through infected body fluids, including blood, semen, and vaginal fluids (including menstrual blood).It also can be transmitted from a pregnant woman to her child at or near the time of birth.  Hepatitis B surface antigen (HBsAg) is one of the most frequently performed tests for HBV. This HBV antigen is the earliest indicator of an active hepatitis B infection. This antigen may be present before symptoms of an HBV infection are present. If this antigen level remains high for more than 6 months, then you will probably become a carrier of HBV, meaning you can transmit it to others throughout your life.  Hepatitis B surface antibody (HBsAb) is also one of the most common tests for HBV. Usually this antibody appears about 4 weeks after HBsAg disappears and means that the infection is at the end of its active stage and you cannot pass the virus to others (you are no longer contagious). This antibody also protects you from getting HBV again in the future. The test is done to determine the need for vaccination; the antibody will be present after receiving the HBV vaccine series, showing that you have protection (immunity) from the virus. Occasionally your test may show that you have both the HBsAb and HBsAg antibodies; in this case, you are still contagious.  Hepatitis B core antigen (HBcAg). Currently, there is no test to find this antigen.  Hepatitis B core antibody (HBcAb) is an antibody to the hepatitis B core antigen. This antibody appears about 1 month after an active HBV infection. It can be found in people who had an infection in the past and in those with long-term (chronic) HBV. It usually is present for life.  Hepatitis B core antibody IgM (HBcAbIgM) is also an antibody to the hepatitis B core antigen. It shows a recent infection in the last 6 months.  Hepatitis B e-antigen (HBeAg) is an HBV protein that is only present during an active HBV infection. This test determines how contagious you are. Testing for this antigen can also be used to monitor the effectiveness of treatment for HBV.  Hepatitis B e-antibody (HBeAb) shows that the active stage of the HBV infection is almost over and your risk of being contagious is greatly reduced. HBeAb is usually present during chronic HBV infections.  HBV DNA testing finds genetic material (DNA) from the hepatitis B virus. Currently, quantitative HBV DNA tests are done. A high HBV DNA level means that the virus is multiplying in your body and you are very contagious. If you have a chronic HBV infection, an elevated viral DNA level means you are at an increased risk for chronic hepatitis and may want to consider treatment with medications. Testing for HBV DNA also is important to monitor the effectiveness of treatment for chronic HBV infection. HBV DNA testing is a more sensitive test than HBeAg (above) for detecting HBV in the blood.Hepatitis B vaccine is available to prevent an HBV infection.
    • Hepatitis B SerologyHepatitis B virus (HBV) is a small double stranded DNA virus composed of an outer envelope containinghepatitis B surface antigen (HBsAg) and an inner nucleocapsid consisting of hepatitis B envelope antigen(HBeAg) and hepatitis B core antigen (HBcAg). The viral core also contains a double stranded DNAgenome and DNA polymerase.HBV infection can result in both acute and chronic hepatitis. Approximately 90% of adults who areinfected will resolve the infection without permanent organ damage, while 10% become carriers and 6%progress to chronic disease. Infected newborns and children have a much worse outcome. Chronicinfection occurs in 90% of infants infected at birth and in 30% of children infected between ages 1 and 5years.After exposure to HBV, there is an incubation period ranging from 45 to 180 days, during which thepatient will not exhibit symptoms or positive serologic results. Symptoms, if they appear, usually occurwithin 4 to 6 weeks after exposure. The most common symptoms include nausea, anorexia, malaise andjaundice. The stage of the infection can be monitored with tests for HBV antigens and antibodies.HBsAg is the first serologic marker, developing between 6 weeks and 6 months following infection, butprior to onset of symptoms. Presence of HBsAg in serum may indicate acute HBV infection, chronic HBVinfection, or asymptomatic carrier state. In acute infection, HBsAg usually disappears within 1 to 2months after onset of symptoms. HBsAg persists in patients with chronic hepatitis. The significance of apositive test for HBsAg is determined by evaluating it in relationship to the presence or absence of theother HBV markers and the clinical presentation and history of the patient.Antibody to HBsAg (Anti-HBs) becomes detectable several weeks after HBsAg has disappeared. Theinterval between disappearance of HBsAg and appearance of anti-HBs is known as the window periodand may last as long as 6 months. Detection of anti-HBs usually indicates clinical recovery andsubsequent immunity to HBV. Anti-HBs may persist after resolution of the infection. Therefore, thedetection of anti-HBs does not discriminate between current or previous infection.The clinical relevance of anti-HBs detection is in establishing complete resolution of the infection and theacquisition of immunity, whether acquired as a result of natural HBV infection or vaccination. Anti-HBsmay fall below detectable levels with time.Successful vaccination results in detectable anti-HBs. Levels of 10 mIU/mL or greater indicate protectionagainst HBV infection. Anti-HBs quantitation is a useful tool to monitor vaccinees who are likely to havea blunted response incuding:  Individuals > 30 years of age at the time of first vaccination  Immunocompromised patients  Obese individuals  Patients undergoing dialysis  Patients with protein losing nephropathies  Individuals working in high risk endemic areasHBeAg develops one week after HBsAg is detectable, but before symptoms appear. The presence ofHBeAg correlates with the level of infectivity; a patient is most likely to transmit the virus when HBeAgis present. HBeAg usually disappears about 3 weeks before HBsAg disappears. Persistence of HBeAgbeyond 12 weeks usually indicates progression to a chronic carrier state. Pregnant women who arepositive for HbeAg have a high risk (90%) of HBV transmission to the fetus.Antibody to HBeAg (anti-HBE) is usually detectable between 12 and 16 weeks, when HBeAg disappears.When a patient is positive for HBsAg and anti-HBE, but negative for HBeAg, there is reduced infectivityand a probable likelihood of resolving the infection. Anti-HBe may be detectable in a chronic carrier. Thepresence of anti-HBe does not imply immunity to HBV.Antibody to HBcAg (anti-HBc) appears during the first few weeks after infection, shortly after the onsetof symptoms and rises to high levels during convalescence. IgM anti-HBc develops in the acute phase ofHBV infection, indicating an infection in the past 3 to 6 months. It is detectable during prodromal, acute,and early convalescent phases. IgM anti-HBc may be the only antibody detectable during the windowperiod when HBsAg has disappeared and before anti-HBs becomes detectable. In this situation, it isconsidered to be a reliable indicator of ongoing infection. Prenatally acquired anti-HBc graduallydisappears in the first 2 to 4 months of life.
    • IgG anti-HBc develops in the late acute phase of infection. It is measured as part of total anti-HBc andmay be the only serologic marker remaining following recovery from infection. It is an accurateserological marker of previous HBV infection, as it appears in all patients infected with the hepatitis Bvirus and may persist in individuals at low titer long after HBV exposure. In some cases, total anti-HBctiters may fall into the undetectable range along with total anti-HBs.In subclinical asymptomatic hepatitis B virus infection, HBsAg and HBeAg are present for a brief periodor may not be detectable and are followed by the appearance of anti-HBc and anti-HBs. In thesepatients, detection of total anti-HBc and total anti-HBs must be relied on as evidence of previous HBVinfection.Chronic infection is defined as the absence of concurrent hepatitis B core IgM antibody (IgM anti-HBc)and by persistence of HBsAg or HBV DNA for at least 6 months. In chronic hepatitis B infection, HBsAgappears during the incubation phase of the disease and may persist for years and possibly for life. Totalanti-HBc also appears during this early phase and rises in titer. The highest titers of total anti-HBc arefound in the chronic HBsAg carrier state. All HBsAg-positive persons are considered infectious.The presence of HBV DNA in the plasma is an accurate indicator of viral replication. HBV DNA levels thatpersist longer than 8 weeks may indicate progression to chronic HBV infection. Anti- Anti- Anti- HBc HBc Anti- HBsAg HbeAg Interpretation HBs HBe Total IgM Early HBV infection, + - - asymptomatic + + + Acute HBV hepatitis Chronic HBV + - + - infection Chronic HBV + _ + - hepatitis,replicating HBV exposure with +/- + recovery/immunityIn October 2008, the Centers for Disease Control (CDC) released new guidelines which expand thetesting recommendations for chronic hepatitis B (HBV) infections. Although the incidence of new HBVinfections has declined due to vaccine availability, there are an estimated 800,000 to 1.4 million peoplewith chronic HBV infections in the U.S. Because the disease can be asymptomatic for years, those withchronic HBV may be unaware of their infection, and are at high risk for late complications of the diseaseas well as potentially transmitting the virus. There are an estimated 2,000 to 4,000 deaths in the U.S.annually attributed to hepatitis B infection, mostly due to cirrhosis and liver cancer.Previously, the CDC recommended hepatitis B screening for pregnant women & infants of HBV-infectedmothers, household contacts and sex partners of HBV-infected individuals, HIV-infected people, personsborn in countries with HBV prevalence >8%, and post-occupational exposure. The new guidelinesexpand the testing recommendation to include essentially three new groups:  Patients receiving cytotoxic or immunosuppressive therapy, including chemotherapy, organ transplant recipients, and those treated for rheumatologic or gastroenterologic disease.  People born in geographic regions with HBV prevalence >2%. This includes Eastern Europe, Asia, the Middle East, and Pacific Islands.  People with behavioral exposures to HBV, including past or current injection drug users, and men who have sex with men.The new guidelines also include recommendations for medical management of chronic HBV and areavailable through www.cdc.gov, MMWR Recommendations and Reports, September 19,2008; Vol. 57(RR-8).
    • Hepatitis B Surface AntibodyHepatitis B surface antibody is the immunity conferring antibody that appears after infection with thehepatitis B virus. It is also detectable following vaccination for hepatitis B. Both qualitative andquantitative tests are available. Qualitative results are reported as positive or negative. A positive resultcorresponds to an antibody level greater than 10 mIU/mL, which is indicative of immunity. For mostpurposes, including screening for previous hepatitis B infection and routine post-vaccination follow-up,the qualitative assay is the test of choice, and is less expensive than the quantitative assay.Specimen requirement is one SST tube of blood.
    • Hepatitis B Viral Load 80% of patients with inactive HBV have detectable low level DNA, usually < 500,000 copies/mL Patients with normal LFT, E antibody positive & low level DNA should still be considered to have inactive disease and should not be Rxed HBV Genotypes  7% A (Best response to IF)  27% B  51% C  15% D Genotyping will become important to determine candidates for IF vs antiviral Rx  Peg IF  Lamivudine, Adefovir, Entecovir, Ldt HBV resistance testing will become important with introduction of new antiviral medications
    • Hepatitis C Virus Test Test OverviewHepatitis C virus tests detect substances in the blood that indicate a hepatitis infection is active, chronic, or hasoccurred in the past. The tests detect proteins (antibodies) or genetic material (DNA or RNA) of the virus that causeshepatitis. It is important to identify the type of hepatitis virus causing infection so that its spread can be prevented andthe proper treatment can be started immediately.Hepatitis C virus (HCV) testingHCV is transmitted through infected blood.  Anti-HCV antibody tests detect the presence of antibodies to HCV in the blood, indicating an HCV infection has occurred. However, this test makes no distinction between an acute or chronic infection. The enzyme immunoassay (EIA) may be the first test done to detect anti-HCV antibodies. Sometimes a supplemental test called the recombinant immunoblot assay (RIBA) may be done to confirm a positive EIA test result.  HCV RIBA is an additional test that detects antibodies to HCV. This test can tell whether a positive result was from an actual HCV infection or whether the result was a false-positive.  HCV genetic material (RNA) testing uses polymerase chain reaction (PCR) to detect the RNA of an active hepatitis C infection. The RNA can be detected in a persons blood within 1 to 2 weeks after exposure to the virus. HCV RNA testing may be done to confirm a positive result on an HCV antibody test, define the level of virus in the blood (called viral load), or predict the likelihood that a person with HCV will respond to medical treatment. Another RNA test called genotyping can define the strain of hepatitis C and indicate how likely it is to respond to treatment.  HCV quantitative test or viral load are often used before and during treatment to determine how long treatment needs to be given and to monitor your response to treatment.  HCV viral genotyping is used to determine which genotype of the HCV virus is present. HCV has 6 genotypes, and some are more responsive to treatment than others.There is no preventive vaccine available for hepatitis C.Why It Is DoneHepatitis virus testing is done to:  Diagnose and identify the type of hepatitis virus causing the infection. Other tests that indicate how well the liver is functioning are usually done to support a diagnosis of hepatitis. (See the What to Think About section.)  Screen people (such as doctors, dentists, and nurses) who have an increased risk of getting or spreading a viral hepatitis infection.  Screen potential blood donors and donor organs to prevent the spread of hepatitis.  To further evaluate abnormal liver function tests.How To PrepareNo special preparation is needed before having hepatitis virus testing.Tell your health professional whether you are taking any herbs or natural substances, because some of these productsmay affect your test results.Talk to your health professional about any concerns you have regarding the need for the test, its risks, or how it will bedone. To help you understand the importance of this test, fill out the medical test information form (What is a PDFdocument?).How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.
    •  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsHepatitis C virus tests detect substances in the blood that indicate a hepatitis infection is active, chronic, or hasoccurred in the past. The tests detect proteins (antibodies) or genetic material (DNA or RNA) of the viruses that causehepatitis. Normal results of hepatitis virus testing are called negative. This means that no antibodies or genetic materialof a hepatitis virus were found.Abnormal (positive) Hepatitis C virus tests Hepatitis C antibodies are detected. A test to detect HCV RNA will be needed to determine whether you Hepatitis C have an acute infection. The six major strains of HCV can be identified by determining their genetic (HCV) makeup (genotyping). Hepatitis C genetic material (RNA) is detected. This result indicates an acute hepatitis C infection.What Affects the TestHerbs and other natural products may interfere with the accuracy of the results.What To Think About  There is no vaccine at this time to prevent infections with the hepatitis C virus.  Hepatitis antibodies can take weeks or months to develop, so a person infected with hepatitis may initially test negative if testing is done early in the infection.  All donated blood is tested for hepatitis before being used.  Other tests that indicate how well the liver is functioning are usually done to support a diagnosis of hepatitis. These tests can include measuring levels of bilirubin, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase. For more information, see the medical tests Bilirubin, Alkaline Phosphatase, Alanine Aminotransferase (ALT), and Aspartate Aminotransferase (AST).  In many states, some types of hepatitis infections must be reported to the local health department. The health department can then issue a warning to other people who may have been infected with the hepatitis virus, such as those who are close contacts of someone with hepatitis C.  A home test kit is available for hepatitis C (HCV). The kit contains a sharp instrument (lancet) that you use to draw a small sample of blood from your fingertip. The blood sample is then placed on a piece of collection paper and mailed in a prepaid envelope to a lab for testing. Results are available in 10 days. You are given an identification number to use when calling a toll-free number to obtain
    • confidential results. If the results of the test are positive, it is important for you to make an appointment with your health professional to confirm the test results, determine the amount of damage to your liver, and determine whether antiviral therapy is an option. Hepatitis C RNA testing is done to confirm a positive result on a hepatitis C virus (HCV) antibody test or to indicate how likely a person with HCV will respond to medical treatment.
    • Hepatitis C GenotypingAt least six major genotypes of Hepatitis C (HCV), each with multiple subtypes, have been identifiedworldwide. Genotypes are designated with numbers (genotypes 1-6) and subtypes with letters. HCVgenotypes 1, 2, and 3 appear to have a worldwide distribution, but their prevalence varies from onegeographic area to another.  Subtypes 1a and 1b are the most common genotypes in the United States and Europe.  Subtype 1b is the most frequent subtype in Japan.  Subtypes 2a and 2b are found in North America, Europe, and Japan.  Subtype 2c is prevalent in northern Italy.  Subtype 3a is detected in IV drug users in Europe and the United States.  Genotype 4 is identified in North Africa and the Middle East.  Genotypes 5 and 6 are predominant in South Africa and Hong Kong, respectively.The United States has approximately:  70% genotype 1  16% genotype 2  13% genotype 3  < 1% genotypes 4-6HCV genotyping helps predict the outcome of therapy and influences the choice of treatment. Currently,the only clinically relevant distinction is between genotype 1 and genotypes 2 and 3. Studies have shownthat patients infected with genotype 1 are less likely to have a sustained favorable response totreatment than patients with genotypes 2 and 3. Other predictors of response to antiviral therapy areviral load of less than 2,000,000 IU/mL, shorter duration of infection, female gender, and low bodyweight.  With Pegylated IF/Ribivarin, a 2 log drop in viral load in first 12 wks indicates a sustained virologic response  If virus is not undetectable by 24 weeks, a patient will most likely relapse  Two patterns of no response are seen:  Null response = dont see 2 log drop in first 12 weeks; stop therapy  Partial response = achieve 2 log drop in first 12 weeks, but viral load stabilizes & doesnt decrease further; stop Rx at 24 wks because patients wont become viral negative  Genotype 1 has 20% null responders  80% early response within 12 weeks  65% become viral negative  40 - 50% have a sustained viral response  Genotype 2 has 3% null responders  97% have early virologic response  90% have sustained viral responseA single specimen can be used to determine both genotype and viral load. The specimen requirement isone SST, EDTA or ACD tube of blood. Samples collected in heparin tubes are unsuitable for analysis.
    • Hepatitis C Test RecommendationsMuch knowledge about the natural history of hepatitis C (HCV) infection has been gained in the lastseveral years and treatment strategies have improved. Likewise, laboratory testing for HCV has evolved.Initially, only serologic assays were available. Screening for HCV antibody by EIA was followed by aconfirmatory immunoblot, the RIBA. If both assays were positive, infection was established.Within the past 10 years, molecular assays that directly detect viral particles have been developed.Molecular assays utilizing PCR technology can be qualitative or quantitative. Qualitative assays are moresensitive and reproducible than quantitative assays. In addition, PCR and DNA sequencing technologycan now be used to establish the HCV genotype. Currently available assays and their major features arelisted in the following table. Assay Optimal Use Initial screening test for HCV Antibody EIA chronic infection Confirm positive antibody if PCR HCV Immunoblot qualitative test negative Most sensitive PCR assay HCV PCR Detect viremia Qualitative Assess response to therapy Detect acute infection HCV PCR Establish viral load prior to therapy Quantitative HCV Genotype Guide therapeutic decisionsfor diagnosing HCV infection and assessing therapeutic response. A recent review (NEJM 2001;345:41-52) summarized current thinking about optimal use of serologic and molecular tests. The most cost-effective algorithm is based on the following principles:  HCV infection is most often detected by HEP C ABY EIA. Positive results should be confirmed by HCV PCR QL, which detects 50 IU/mL of virus, rather than HCV PCR QT, which detects 600 IU/mL. Persons who are EIA and PCR positive are infected and viremic.  HCV RIBA should be used to confirm HEP C ABY EIA positive results if HCV PCR QL is negative. Persons who are EIA and RIBA positive but PCR negative are infected but not viremic.  HEP C ABY EIA results may be negative in HCV infected individuals who are immuno- compromised or in the acute phase of infection. HCV PCR QL will detect viremia in these individuals.  HCV PCR QT and HCV GENO should be performed prior to therapy to determine viral load and genotype, which guide therapeutic decisions. Currently, the only relevant genotype distinction is between genotype 1 and genotypes 2 and 3.  HCV PCR QL should be used at 24 weeks, 48 weeks, and 6 months after treatment to assess response.
    • Hepatitis C Virus AntibodyHepatitis C virus (HCV) infection is the most common chronic blood-borne infection in the United States.It is estimated that 40% of chronic liver disease is HCV related and HCV-associated end-stage liverdisease is the most frequent indication for liver transplantation among adults.Acute hepatitis C is generally a benign disease. In transfusion transmitted infections, where the acuteonset is best documented, 70% of cases are anicteric and asymptomatic; 30% have a bilirubin greaterthan 2.5 mg/dL and the mean peak ALT is 700 U/L. However, patients with community acquired acuteHCV, usually present with overt clinical illness; 70% are icteric and 75% have ALT levels that exceed 15times the upper limit of normal. Approximately 50% of infected individuals evolve into chronic liverdisease. Chronic hepatitis C infection is the primary indication for liver transplantation.The Centers for Disease Control and Prevention (CDC) has recommended routine testing for HCV for thefollowing groups (MMWR 1998; 47, No. RR-19):  Persons who ever injected illegal drugs, including those who injected once or a few times many years ago and do not consider themselves drug users.  Persons with selected medical conditions, including  Persons who received clotting factor concentrates produced before 1987  Persons who were ever on chronic hemodialysis  Persons with persistently abnormal alanine aminotransferase (ALT) levels  Prior recipients of transfusions or organ transplants, including  Persons who were notified that they received blood from a donor who later tested positive for HCV infection  Persons who received a transfusion of blood or blood components before July 1992  Persons who received an organ transplant before July 1992Persons with other recognized exposures to HCV including occupational exposure through needles orother sharps and children born to HCV-positive mothers should also be tested.The recommended initial test is enzyme immunoassay (EIA) for HCV antibody. The first enzymeimmunoassay (EIA), which detected antibody to a single viral antigen, was introduced in 1989. In 1992,this screening test was replaced by a more sensitive second generation EIA, which detects antibody toseveral viral antigens. Sensitivity of the current assay is 97%. It does not distinguish between acute,chronic, or resolved infection. The window period may be as long as 24 weeks. Only 40% of patientshave detectable antibody within 10 weeks of infection and 80% have demonstrable antibodies at 15weeks. Transplant patients and immunosuppressed patients may not produce detectable antibodyfollowing infection.Another shortcoming of HCV antibody testing is the significant number of false positive results amonglow-prevalence populations. For an immunocompetent population with HCV prevalence of < 10%, thechance of a false positive antibody test ranges from 15-60%.Another striking feature of HCV is its genetic heterogeneity, which has produced multiple mutantviruses. Patients infected with less common variants mount different antibody responses that may notbe detected by current EIA, since these tests are based on the predominant HCV genotype found in theU.S.The CDC published updated guidelines for reporting of HCV antibody in 2003(MMWR 2003;52 No. RR-3)based upon data review from thousands of tests from populations with HCV prevalence ranging from 2%to 25%. CDC recommended that HCV antibody reports should include the signal to cut-off (S/CO) ratio,which is calculated in the laboratory by dividing the value of the patients sample by the value of thenegative-positive cut-off point for that run.  Samples with an S/CO ratio < 3.8 have a > 95% probability of predicting true positive anti-HCV and are indicative of past or present infection. Supplemental testing by qualitative or quantitative PCR on these patients allows assessment of viral activity. HCV genotyping can be performed simultaneously on samples with detectable virus by PCR.  Samples that are reactive for HCV antibody, but have an S/CO ratio < 3.8 may be false positive and require supplemental testing to determine the true HCV status. False positive tests are seen most often in the elderly, dialysis patients, and patients with autoimmune disease. These samples should have confirmatory testing by qualitative HCV PCR.
    • Specimen requirement is one SST tube of blood. PCR & genotype testing can usually be performed onthe residual serum sample used for the HCV antibody test.
    • Hepatitis C Virus RNA by PCRHepatitis C virus (HCV) is the most frequent cause of parenterally transmitted and sporadic chronic non-A, non-B hepatitis. As many as 175,000 people acquire hepatitis C annually in the U.S. The mostcommonly identified source of exposure is intravenous drug abuse, accounting for 40% of cases. Bloodtransfusion is responsible for only 5% of cases. The majority of cases have no identifiable exposuresource. Unlike hepatitis B, sexual and maternal-fetal transmissions are uncommon.Acute hepatitis C is generally a benign disease. In transfusion transmitted infections, where the acuteonset is best documented, 70% of cases are anicteric and asymptomatic; 30% have a bilirubin greaterthan 2.5 mg/dL and the mean peak ALT is 700 U/L. However, patients with community acquired acuteHCV, usually present with overt clinical illness; 70% are icteric and 75% have ALT levels that exceed 15times the upper limit of normal. Approximately 50% of infected individuals evolve into chronic liverdisease. Chronic hepatitis C infection is the primary indication for liver transplantation.Laboratory diagnosis of HCV infection depends upon detection of circulating antibodies. The first enzymeimmunoassay (EIA), which detected antibody to a single viral antigen, was introduced in 1989. In 1992,this screening test was replaced by a more sensitive second generation EIA, which detects antibody toseveral viral antigens. In addition, a recombinant immunoblot assay (RIBA) was licensed as asupplemental test to confirm EIA positive results.Many problems exist with current HCV antibody tests. False positive EIA results occur due to nonspecificreactions associated with storage of sera, hypergammaglobulinemia, paraproteinemia, rheumatoid factorpositive sera and other autoimmune diseases, and recent influenza vaccination. Only 30-40% of EIAreactive samples are confirmed by RIBA in a low risk population. Among high-risk populations, or inpatients who are both EIA reactive and have elevated ALT levels, the confirmation rate increases to70%. Unfortunately, a significant number of EIA positive samples are not adequately resolved by RIBAand are reported as indeterminate.Another problem with antibody testing is its insensitivity. A long lag time exists between infection andantibody detection. Only 40% of patients have detectable antibody within 10 weeks of infection and80% have demonstrable antibodies at 15 weeks. The window period may be as long as 24 weeks.Transplant patients and immunosuppressed patients may not produce detectable antibody followinginfection. Another striking feature of HCV is its genetic heterogeneity, which has produced multiplemutant viruses. Patients infected with less common variants mount different antibody responses thatmay not be detected by current EIA and RIBA, since these tests are based on the predominant HCVgenotype found in the U.S. Finally, HCV antibodies persist for life in chronically infected patients andrarely disappear on recovery. Therefore, HCV antibody tests cannot distinguish between current,resolving, or past infections.Many of these problems can be resolved with subsequent testing by polymerase chain reaction (PCR) forhepatitis C RNA. PCR testing has been available since September 1995. In this assay, a DNA copy ofviral RNA is synthesized by reverse transcription. This DNA molecule is amplified millions of times byPCR. The sensitivity of PCR is approximately 1000 viral genomes per mL of blood. Because of its highsensitivity, PCR can detect HCV infection much sooner than antibody tests. Most patients havedetectable levels of HCV RNA in plasma within 1 to 2 weeks of exposure. HCV RNA detection precedesALT elevation by 10 to 12 weeks and seroconversion by 10 to 24 weeks. The highest levels of circulatingviral RNA are found during the early course of infection, suggesting that patients are most infectiousduring this time. Variation among HCV genotypes is less likely to affect PCR test performance thanantibody tests, because PCR primers are based on the highly conserved untranslated region of the HCVgenome.PCR is useful in resolving ambiguous EIA/RIBA results. As many as 50% of patients who are EIA positiveand RIBA indeterminate have detectable HCV RNA by PCR. Following seroconversion, PCR can bevaluable in differentiating acute resolving HCV disease from chronic HCV infection in which viral RNApersists. In acute resolving HCV, RNA levels decrease rapidly, even before ALT levels. In the near future,quantitative HCV RNA tests will be available. Pretreatment levels will be particularly useful indetermining which patients are the best candidates for interferon therapy. Posttreatment levels will behelpful in monitoring therapeutic response.Reference value is negative for HCV-RNA.Specimen requirement is one SST tube of blood. Tubes containing heparin cannot be used. Serum needsto be separated from cells within six hours of collection and refrigerated or frozen to avoid degradationof viral RNA. Following separation, serum can be frozen and stored for prolonged periods.
    • Hepatitis C Quantitative PCRHepatitis C (HCV) is a major cause of chronic liver disease in the United States. Approximately 4 millionpeople in the United States are currently infected and an estimated 40,000 new infections are suspectedeach year. The initial diagnosis of HCV infection is based on positive HCV antibody tests and thedetection of HCV RNA by qualitative PCR.The initial test for hepatitis C (HCV) infection is an immunoassay that detects antibodies to multiple HCVproteins. Supplemental or confirmatory testing is recommended for all reactive HCV antibody tests todetermine the presence of active infection. Detection of HCV RNA in the blood by polymerase chainreaction (PCR) is indicative of active infection. PCR testing has been available since September 1995. Inthis assay, a DNA copy of viral RNA is synthesized by reverse transcription. This DNA molecule isamplified millions of times by PCR. Because of its high sensitivity, PCR can detect HCV infection muchsooner than antibody tests. Most patients have detectable levels of HCV RNA in plasma within 1 to 2weeks of exposure. HCV RNA detection precedes ALT elevation by 10 to 12 weeks and seroconversion by10 to 24 weeks. The highest levels of circulating viral RNA are found during the early course of infection,suggesting that patients are most infectious during this time. Variation among HCV genotypes is lesslikely to affect PCR test performance than antibody tests, because PCR primers are based on the highlyconserved untranslated region of the HCV genome.Two types of PCR assays are available; qualitative and quantitative. In the past, qualitative PCR had alower limit of detection (50 IU/mL) than quantitative Amplicor PCR (600 IU/mL) and was used both as aconfirmatory test for anti-HCV and as an end-of-therapy assay. Quantitative HCV PCR was the preferredtest for determining viral load prior to therapy, along with HCV genotype.Once HCV infection has been established, quantitative HCV PCR (viral load) can provide prognosticinformation. Treatment response has been shown to be greater for patients with low levels of HCV RNA.Most HCV infected patients should have viral load testing performed prior to treatment unless there areclear contraindications to antiviral therapy. The HCV positive patient with negative viral load should havethe test repeated in 3 to 4 months, because some patients with active infection have intermittentlyundetectable viral loads.Predictors of response to antiviral therapy include viral load of less than 2,000,000 IU/mL, genotypeother than 1, shorter duration of infection, female gender, and low body weight.  With Pegylated IF/Ribivarin, a sustained virologic response is indicated by a 2 log drop in viral load in first 12 wks  If virus is not undetectable by 24 weeks, a patient will most likely relapse  Two patterns of no response have been seen:  Null response = dont see 2 log drop in first 12 weeks; stop therapy  Partial response = achieve 2 log drop in first 12 weeks, but viral load stabilizes & doesnt decrease further; stop Rx at 24 wks because patients wont become viral negative  Genotype 1 has 20% null responders  80% early response within 12 weeks  65% become viral negative  40=50% have a sustained viral response  Genotype 2 has 3% null responders  97% have early virologic response  90% have sustained viral responseThe Roche Taqman real time quantitative PCR method, which has a lower limit of detection of 50 - 80IU/ml (Hillyard, Valsamakis, 2005 Roche Molecular Advisory Board). This lower limit of detectionobviates the need for qualitative PCR. The new method is also linear up to 200 million IU/mL in theupper range. With the switch from Amplicor to Taqman, 10% of patients that had undetectable HCV viralloads by the Amplicor method are positive by Taqman real time PCR. This change in viral status is due tothe decrease in the lower limit of detection from 600 to 80 IU/mL. The specimen requirement for HCVRNA by PCR is one EDTA, ACD, or SST tube of blood. Tubes containing heparin cannot be used. Serumneeds to be separated from cells within 6 hours of collection and refrigerated or frozen to avoiddegradation of viral RNA. HCV PCR and genotype can usually be performed on residual specimen fromanti-HCV testing. Client services can be contacted at 932-3850 to add an order for HCV RNA by PCR.
    • Hepatitis C Virus RIBARecombinant Immunoblot assay (RIBA) is a supplemental test for a reactive HCV antibody. Theimmunoblot assay utilizes four recombinant HCV-encoded antigens, which are immobilized as individualbands on test strips. The strips are incubated with patient serum, and if present, antibodies to HCV willbind to the corresponding antigen bands on the strip.A positive result indicates past or current hepatitis C infection. This test is not useful for detection ofearly acute hepatitis C infection or for differentiation between resolved and chronic hepatitis C infections.Indeterminate results may occur during seroconversion after recent infection, or with chronic infection.Indeterminate results may also indicate a false positive HCV antibody EIA, particularly in a person at lowrisk for HCV infection.Results are reported as reactive, indeterminate or non-reactive.Specimen requirement is one plain red top or one SST tube of blood. Refrigerate after collection.Centrifuge SST tube within 20-30 minutes of draw.
    • Hepatitis D virus (HDV) testingInfection with the hepatitis D virus (HDV), or delta agent, occurs only in people who are already infected with thehepatitis B virus (HBV). Vaccination against hepatitis B will prevent hepatitis D infection. Hepatitis D infection is rare inthe United States and Canada, except among people who inject illegal drugs and those who are frequently exposed toblood products. The hepatitis D test detects HDV antibodies. A positive test indicates only that you have been infectedwith HDV—it cannot distinguish between an acute or chronic infection. Another test, the HDV RNA test, is needed todetermine whether you have an active HDV infection. It does not distinguish between an acute or chronic infection.However, this test currently is not available except in research settings.Since hepatitis B infections can be spread through sexual contact, practice safe sex until your test results are returned.Why It Is DoneHepatitis virus testing is done to:  Identify the type of hepatitis virus causing the infection. Other tests that indicate how well the liver is functioning are usually done to support a diagnosis of hepatitis. (See the What to Think About section.)  Screen people who have an increased risk of getting or spreading a viral hepatitis infection, such as doctors, dentists, and nurses.  Screen blood donors and donor organs to prevent the spread of hepatitis.  Find out if a person has developed antibodies after receiving vaccinations for hepatitis B. The presence of antibodies to hepatitis B virus (HBsAb) means that the vaccinations were effective.  Check abnormal liver function tests.How To PrepareNo special preparation is needed before having hepatitis virus testing.Tell your health professional whether you are taking any herbs or natural substances, because some of these productsmay affect your test results.Talk to your health professional about any concerns you have regarding the need for the test, its risks, or how it will bedone. To help you understand the importance of this test, fill out the medical test information form (What is a PDFdocument?).How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.Risks
    • Blood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsHepatitis B virus tests look for substances in the blood that show a hepatitis infection is active, ongoing (chronic), or hasoccurred in the past. The tests look for antigens, proteins (antibodies), or genetic material (DNA or RNA) of the virusesthat cause hepatitis. Normal results of hepatitis virus testing are called negative. This means that no antigens,antibodies, or genetic material of a hepatitis virus were found.Abnormal (positive) Hepatitis B and D virus tests Hepatitis B Hepatitis B (HBV) antibodies and/or antigens are detected. Additional tests may be needed to (HBV) determine whether you have an acute or chronic HBV infection.  Hepatitis B surface antigen (HBsAg) shows an active infection. If the test is positive for more than 6 months, this means you are a chronic carrier. You can spread the HBV infection to others.  Hepatitis B surface antibody (HBsAb) shows the end of active infection and protection against HBV for life. It also can show protection from having received the HBV vaccine. Occasionally your test may show that you have both the HBsAb and HBsAg antibodies; in this case, you are still contagious.  Hepatitis B core antibody (HBcAb) shows that you have been infected with HBV. It does not tell the difference between a past or present infection.  Hepatitis B core antibody IgM (HBcABIgM) shows a recent infection in the last 6 months.  Hepatitis B e-antigen (HBeAg) shows an active contagious state.  Hepatitis B e-antibody (HBeAb) shows the end of an HBV infection. You are less contagious but can still infect others.  HBV DNA testing finds genetic material (DNA) from the hepatitis B virus. Hepatitis D Hepatitis D antibodies are found. However, this test cannot tell the difference between an (HDV) acute or chronic infection. Hepatitis D can only be present if hepatitis B is present.What Affects the TestHerbs and other natural products may interfere with the accuracy of the results.What To Think Aboutzaffrex  Hepatitis B can be prevented by vaccination. The presence of antibodies to the hepatitis B virus can indicate that you have developed immunity to the infection after being vaccinated. A hepatitis B infection must be present for a hepatitis D virus infection to occur; the hepatitis B vaccination protects against hepatitis D infection as well.  Hepatitis antibodies can take weeks or months to develop, so a person infected with hepatitis may initially test negative if testing is done early in the infection.  People who have received the hepatitis B vaccination can have positive HBsAb test results, while all other Hepatitis B results (HBcAb, HBeAb, HBsAg, HBeAg, and HBV DNA) are negative. However, a
    • vaccinated person who is exposed to someone with an HBV infection may have a positive HBcAb test. All donated blood is tested for hepatitis before being used. Other tests that indicate how well the liver is functioning are usually done to support a diagnosis of hepatitis. These tests can include measuring levels of bilirubin, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase. For more information, see the medical tests Bilirubin, Alkaline Phosphatase, Alanine Aminotransferase (ALT), and Aspartate Aminotransferase (AST). In many states, some types of hepatitis infections must be reported to the local health department. The health department can then issue a warning to other people who may have been infected with the hepatitis virus, such as those who are close contacts of someone with hepatitis B.
    • Hepatitis Test RecommendationsAcute viral hepatitis is a frequent cause of liver disease and is generally caused by hepatitis A, B, or C inthe United States. Hepatitis D occurs as a coinfection in patients with hepatitis B and is rare in thiscountry. Hepatitis E has been limited to travelers to foreign countries. Feature A B C D E Family Picorna Hepadeno Flavi Satellite Calci Genome RNA DNA RNA RNA RNA Incubation 15-50 d 45-160 d 30-150 d 21-90 d 14-65 d Onset Abrupt Insidious Insidious Insidious Abrupt Oral/fecal Yes No No No Yes Parenteral Rare Usual Usual Usual No Other vectors Food/water Sexual Sexual Sexual? Water Carriers No Yes Yes Yes No Chronicity Rare 25% 75% 10-15% No? Mortality % 0.6 1.4 1 -2 30 1-2The following panels and individual tests are recommended for diagnosis and monitoring of viralhepatitis. Clinical Situation Recommended Tests Acute Hepatitis Screen Anti-HAV IgM, anti-HBc IgM, HBsAg, anti-HCV Hepatitis B Infectivity HBsAg, HBeAg, Anti-HBe Hepatitis B Carrier State HBsAg, HBeAg, Total Anti-HBc Hepatitis B Immunity Anti-HBs & Total Anti-HBc Post Hepatitis B Vaccination Immunity Anti-HBs Hepatitis A Immunity Anti-HAV, Total Hepatitis C Diagnosis Anti-HCV ELISA & Confirmatory PCR Hepatitis C Monitoring HCV Quantitative PCRApproximately 5-10% of community acquired hepatitis is thought attributable to non A-E types, causedby the flavi-like viruses GBV-A, GBV-B, and GBV-C. The recently reported hepatitis G is caused by one
    • strain of GBV-C. While the natural history of these infections is not fully known, they appear to betransmitted parenterally and cause a spectrum of disease from asymptomatic infection through severeliver disease. Currently, no commercial assays are available for serological diagnosis. Medical history and physical exam for HIV infection Exam OverviewWhen you are first diagnosed with HIV, your health professional will check your current health status. He or she will askquestions about your current symptoms and past health to determine whether you have had any HIV-related illnesses,whether you have medication allergies, whether your immunizations are up to date, and whether you have ever beenhospitalized for illness or surgery.Many of the tests a health professional does during the initial exam will be repeated during regular checkups to monitorchanges in your health.Medical historyYou can help your health professional diagnose and treat your condition by being prepared to answer the followingquestions:  Do you have an increased risk for developing HIV? You have an increased risk of developing HIV if you: o Are a man who has sex with men. o Have more than one sex partner, especially if one of you injects drugs. o Inject drugs or steroids, especially if you share needles, syringes, cookers, or other equipment used to inject drugs. o Have sex with a man who has sex with men, has more than one sex partner, or uses injected drugs or steroids. o Have recently had a sexually transmitted disease.  Have you ever had symptoms that might indicate illness, such as fever, weight loss, shortness of breath, or diarrhea?  Have you ever had tuberculosis, fungal or yeast infections, liver infection (hepatitis), cold sores (oral herpes), or any other sexually transmitted diseases? All of these diseases can present special problems for people who are infected with HIV.  Are you a caregiver, such as a partner or parent, of a person who is HIV-positive and has hemophilia?Physical examYour health professional will do a complete physical exam to determine your present state of health. This will include thefollowing examinations:  Temperature. Fevers are common in people who have HIV, even when no other symptoms are present. Fever can sometimes be a sign of a certain kind of infection or cancer that is more common in people who have weakened immune systems. Your health professional will check your temperature at every visit.  Weight. Your health professional will weigh you at every visit. A loss of 10% or more of your body weight is called the wasting syndrome, which is one of the signs of AIDS, the last and most severe stage of HIV infection. You may need help getting adequate nutrition if you have lost weight.  Eyes. Cytomegalovirus (CMV) retinitis is a common complication of AIDS. It occurs more frequently in people who have a CD4+ cell count of less than 100 cells per microliter (µL). Symptoms include seeing floaters, blurred vision, or loss of vision. If you have symptoms of CMV retinitis, you should see an ophthalmologist as soon as possible. Some health professionals recommend ophthalmologist visits every 3 to 6 months if your CD4+ cell count is less than 100 cells/µL.  Mouth. Oral yeast infections (thrush) and other mouth sores are very common in people who are HIV- infected. Your health professional will examine your mouth at every visit. You should have a dental exam at least twice a year. If you develop symptoms of gum disease (periodontal disease), you may need to see your dentist more often.  Lymph nodes. Lymph node enlargement (lymphadenopathy) is not always caused by HIV alone. A biopsy may be considered if your lymph nodes are getting larger or if some are different sizes (asymmetrical). Your health professional will examine your lymph nodes at every visit.  Abdomen. The abdominal exam may show an enlarged liver (hepatomegaly) or enlarged spleen (splenomegaly). These conditions can be caused by new infections or may indicate cancer. Your health professional will do an abdominal exam at every visit or if you develop symptoms such as pain in the upper right or upper left part of your abdomen.
    •  Skin. Skin problems are common for people with HIV infection. A regular exam may reveal treatable conditions ranging in severity from seborrheic dermatitis to Kaposis sarcoma. Your health professional should do a skin exam every 6 months or whenever symptoms develop.  Gynecologic. Women who are HIV-infected have more cervical cell abnormalities than women who do not have HIV. These cell changes can be detected with a Pap test. You should have two Pap tests during the first year after you have been diagnosed with HIV. If the first two Pap tests are normal, you should have a Pap test once a year. You may need to have a Pap test more frequently if you ever have an abnormal test result.Why It Is DoneA thorough physical exam will provide information about your present state of health. During later visits, your healthprofessional will use this information to see whether your health status is changing.The medical history and physical exam are done right after a person has been diagnosed with HIV infection (2 positiveELISA tests and 1 positive Western blot assay).These exams will be done during regular follow-up exams or if specific symptoms develop.ResultsThe medical history and physical exam may provide the following results.NormalNo abnormalities are found. After the initial workup, talk to your health professional to decide how often to schedulefollow-up exams.  The frequency of follow-up exams depends on whether you have symptoms of illness and your initial viral load and CD4+ cell count measurements.  Follow-up exams may be done as often as every 3 to 6 months, possibly more often, especially right after you start medication treatment.If you do not have symptoms but you have a high CD4+ cell count and a low viral load, your health professional willprobably recommend that you have follow-up exams at least every 6 months or sooner if you develop symptoms ofillness.AbnormalSigns of illness are found. Follow-up and treatment will depend upon the specific problem.What To Think AboutYour family medicine physician or internist may not be able to diagnose and treat all the problems that can be causedby HIV infection. Your doctor may refer you to another health professional who specializes in conditions that affectdifferent body systems. Before you make an appointment with a specialist, find out whether he or she has experiencetreating people who have HIV-related illnesses.Complications of HIV may require treatment by the following health professionals:  Cardiologist  Dermatologist  Gastroenterologist  Infectious disease specialist  Oncologist  Ophthalmologist  Orthopedist  Pulmonologist
    • Human Immunodeficiency Virus (HIV) Test Test OverviewA human immunodeficiency virus (HIV) test detects antibodies to HIV in the blood. This determines whether an HIVinfection is present (HIV-positive). HIV infects white blood cells called CD4+ cells, which are part of the bodys immunesystem that help fight infections. HIV causes acquired immunodeficiency syndrome (AIDS), a long-term chronic diseasethat cannot be cured.After the original infection, it takes between 2 weeks and 6 months for antibodies to HIV to appear in the blood. Theperiod between becoming infected with HIV and the point at which antibodies to HIV can be detected in the blood iscalled the seroconversion or "window" period. During this period, an HIV-infected person can still spread the disease,even though a test will not detect any antibodies in his or her blood.Several tests can find antibodies or genetic material (RNA) to the HIV virus. These tests include:  Enzyme-linked immunosorbent assay (ELISA). This test is usually the first one used to detect infection with HIV. If antibodies to HIV are present (positive), the test is usually repeated to confirm the diagnosis. If ELISA is negative, other tests are not usually needed. This test has a low chance of having a false result after the first few weeks that a person is infected.  Western blot. This test is more difficult than the ELISA to perform, but it is done to confirm the results of two positive ELISA tests.  Polymerase chain reaction (PCR). This test finds either the genetic material DNA or RNA of HIV. PCR testing is not done as frequently as antibody testing because it requires technical skill and expensive equipment. This test may be done in the days or weeks after exposure to the virus. Genetic material may be found even if other tests are negative for the virus.  Indirect fluorescent antibody (IFA). This test detects HIV antibodies. Like a Western blot test, it is used to confirm the results of an ELISA. However, it is more expensive than a Western blot test and not commonly used.Testing is often done at 6 weeks, 3 months, and 6 months after exposure to determine that a person is not infected.Why It Is DoneA test for the human immunodeficiency virus (HIV) is done to:  Detect an HIV infection. Testing is often done for people with risk factors for HIV infection and people who have symptoms of an HIV infection.  Screen blood, blood products, and organ donors, to prevent the spread of HIV.  Screen pregnant women for HIV infection. The United States Preventive Services Task Force recommends all pregnant women be screened. Pregnant women who are infected with HIV and receive treatment are less likely to pass the infection on to their babies than are women who do not receive treatment.This test is not done to determine if a person has AIDS. A diagnosis of AIDS means a person is HIV-positive and otherproblems are present.How To PrepareNo special preparation is needed before having this test.A test for HIV infection cannot be done without your consent. Most health professionals offer counseling before andafter the test to discuss:  How the test is done, what the results mean, and any other tests that may be done.  How the diagnosis of an HIV infection may affect your social, emotional, professional, and financial outlooks.
    •  The benefits of early diagnosis and treatment.Before the test, it is important to tell your health professional how and where to contact you when your test results areready. If your health professional has not contacted you within 1 to 2 weeks of your test, call and ask for your results.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsA human immunodeficiency virus (HIV) test detects antibodies to HIV in the blood. This determines whether an HIVinfection is present (HIV-positive). ELISA results are usually available in 2 to 4 days. Results of the other tests, such asthe Western blot or IFA, take 1 to 2 weeks. HIV testsNormal: No HIV antibodies are found. Normal results are called negative. If an antibody test is done during the seroconversion period and is negative, repeat testing is needed. Most people have antibodies to HIV within 6 months after becoming infected. If a repeat test at 6 months is negative, there is no infection. Another test to look for genetic material can be used to find infection in people who still have a negative ELISA but who may have a chance of being infected.Uncertain: Test results do not clearly show whether a person has an HIV infection. This is usually called an indeterminate result. It may occur before HIV antibodies develop or when some other type of antibody is interfering with the results. If this occurs, another test called HIV RNA may be done to see if the virus is present. A person who still has indeterminate results for 6 months or longer is called "stable indeterminate" and is not considered to be infected with HIV.Abnormal: HIV antibodies are found. These results are called positive.
    • A positive ELISA is repeated using the same blood sample. If two or more ELISA results are positive, they must be confirmed by a Western blot or IFA test. The ELISA test can cause false-positive results. No one is considered HIV-positive until he or she has a positive Western blot, IFA, or PCR test.What Affects the TestFactors that can interfere with your test or the accuracy of the results include:  The use of corticosteroids.  Antibody testing during the seroconversion period.  Having AIDS. If a person develops AIDS, his or her body gradually loses its ability to produce the antibodies that fight an HIV infection, so HIV antibody tests may not be accurate.What To Think About  After initial testing, it is important for your health professional to contact you with the results of your test. Be sure to tell your health professional how and where to contact you. If your health professional has not contacted you within 1 to 2 weeks of your test, call and ask for your results.  The ELISA is a good screening test because it is usually positive when an HIV infection is present. However, the ELISA test results can indicate HIV is present when it is not (false-positive). Therefore, the ELISA alone cannot be used to make a definite diagnosis of HIV infection.  Detecting HIV in a newborn infant is difficult. Until about 18 months of age, even a baby who is not infected may still have HIV antibodies received from his or her HIV-positive mother.  To be certain that an HIV infection is not present, a person must test negative for the virus at least 6 months after the last possible exposure to HIV. Testing is often done at 6 weeks, 3 months, and 6 months to determine that a person is not infected.  Home blood test kits to detect an HIV infection are available without a prescription at pharmacies or through mail order. These kits provide instructions and materials for collecting a blood sample that is then sent to a lab for analysis. Results are available over the phone using an anonymous code number. Counseling is also available over the phone for people who use the test kit. Rapid test kits are also available and results are received within a half-hour, compared to 1 to 2 weeks with conventional testing. Positive rapid HIV test results need to be confirmed by a Western blot test.  A screening test for HIV infection may also be done on urine or saliva. An oral HIV test finds antibodies to HIV. Urine testing is rarely done.  Oral test kits that find HIV-1 and HIV-2 in saliva have been approved by the United States Food and Drug Administration (FDA). The test results are provided the same day. These test results need to be confirmed by a Western blot test.  Most states require health professionals, clinics, and hospitals to report confirmed cases of HIV infection to the state health department. Some states allow anonymous reporting (the persons name or other identifying information is not provided). Other states require confidential reporting (identifying information is provided, but only to authorized public health officials). All states must report the numbers of cases of AIDS, without names or other identifying information, to the U.S. Centers for Disease Control and Prevention (CDC).  If you have a positive test result, contact your sex partners to inform them. They may want to be tested. You may be able to get help from your local health department to do this.  Once an HIV infection is present, other tests are done to determine when to treat the infection and how treatment is working. These tests include a CD4+ count and the viral load. For more information, see the medical tests CD4+ Count and Viral Load Measurement.  Two types of HIV have been identified. o HIV-1 causes almost all of the cases of AIDS worldwide. o HIV-2 is found mostly in West Africa.ReferencesOther Works Consulted  Agency for Healthcare Research and Quality (2005). Screening for Human Immunodeficiency Virus Infection (AHRQ Publication No. 05-0580-A). Rockville, MD: Agency for Healthcare Research and Quality. Also available online: http://www.ahrq.gov/clinic/uspstf/uspshivi.htm.
    • Creatinine and Creatinine Clearance Test OverviewCreatinine and creatinine clearance tests measure the level of the waste product creatinine in your blood and urine.These tests provide information about how well your kidneys are working. Creatine is a substance that forms when foodis converted into energy through a process called metabolism. Creatine is broken down into another substance calledcreatinine, which is filtered out of your blood by the kidneys and then passed out of your body in urine. See anillustration of the kidneys .Creatinine is produced at a steady rate and is affected very little by diet or by normal physical activities. If your kidneysare damaged and cannot function normally, the amount of creatinine in your urine decreases while its level in your bloodincreases.Three types of tests involving creatinine can be done:Blood creatinine levelThe blood creatinine level indicates how well your kidneys are working. A high creatinine level may mean your kidneysare not working properly. The amount of creatinine in the blood depends partly on the amount of muscle tissue;therefore, men generally have higher creatinine levels than women.Creatinine clearance testA creatinine clearance test measures how well creatinine is removed from your blood by your kidneys. Compared to ablood creatinine level, a creatinine clearance test provides a more precise measure of how well your kidneys areworking. A creatinine clearance test is performed both on a blood sample taken from your vein and on a sample of urinecollected over 24 hours (24-hour urine sample).Blood urea nitrogen-to-creatinine ratio (BUN:creatinine)The levels of blood creatinine and blood urea nitrogen (BUN) can be used to calculate the BUN-to-creatinine ratio. ABUN-to-creatinine ratio can help your health professional predict which conditions, such as dehydration, may be causingabnormal BUN and creatinine levels and decreased kidney function.Urea is a waste product formed when protein is broken down in your body. Urea is produced in the liver and eliminatedfrom your body in urine. A blood urea nitrogen (BUN) test measures the amount of urea in your blood. Like creatinine, itcan help your health professional predict how well your kidneys are functioning.From the creatinine and BUN levels, a measurement called the BUN-to-creatinine ratio can be calculated. The BUN-to-creatinine ratio is determined by dividing the measured BUN level by the creatinine level.Why It Is DoneA blood creatinine level or a creatinine clearance test is done to:  Determine whether your kidneys are functioning normally.  Monitor the progress of your kidney disease.  Monitor the kidney function of people who take medications that can cause kidney damage.  Determine whether severe dehydration is present. A BUN-to-creatinine ratio can help your health professional predict whether decreased kidney function is the result of dehydration or kidney disease. Dehydration usually causes BUN levels to rise more than creatinine levels, resulting in an increased BUN-to-creatinine ratio. Kidney disease or blockage of the flow of urine from the kidney usually causes both BUN and creatinine levels to increase to a similar degree, resulting in a BUN-to-creatinine ratio that is close to normal.
    • How To PrepareAvoid strenuous exercise 48 hours prior to having creatinine tests.Do not eat an excessive amount [more than 8 oz(227 g)] of meat, especially beef, or other protein for 24 hours prior tothe tests and during a creatinine clearance test.It is important to drink enough fluids during the 24-hour urine collection but avoid coffee and tea which are substancesthat remove water from the body by promoting urine formation and the loss of salt (diuretics).How It Is DoneCollection of the blood sampleThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.Collection of the 24-hour urine sample  The collection period usually starts in the morning. When you first get up, empty your bladder but do not save this urine. Write down the time that you urinated to mark the beginning of your 24-hour collection period.  For the next 24 hours, collect all your urine. Your health professional or lab will usually provide you with a large container that holds about 1 gal(3.8 L) and has a small amount of preservative in it. Urinate into a smaller, clean container and then pour the urine into the large container. Avoid touching the inside of the container with your fingers.  Keep the large container in the refrigerator during the collection period.  Empty your bladder for the final collection at or just before the end of the 24-hour period. Add this final sample to the large container and record the time.  Avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.How It FeelsBlood testYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.Urine testThere is normally no discomfort involved with collecting a 24-hour urine sample.RisksRisks of a blood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.
    •  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.Urine testThere are no risks associated with collecting a 24-hour urine sample.ResultsCreatinine and creatinine clearance tests measure creatinine levels in your blood and urine to provide information abouthow well your kidneys are working. The creatinine clearance value is calculated from the amounts of creatinine in theurine and blood and from the volume of urine. This value is reported as the amount of blood cleared of creatinine perminute, adjusted for your size.NormalNormal results may vary from lab to lab. Blood creatinine and creatinine clearanceBlood creatinine: 0.7–1.2 milligrams per deciliter (mg/dL)Creatinine clearance: 90–140 milliliters per minute (mL/min)Creatinine clearance values normally drop as you get older (normal values usually drop by 6 mL/min for every 10 yearspast the age of 20). BUN-to-creatinine ratioOver 12 months of age: 10:1–20:1Infants less than 12 months of age: Up to 30:1High values  High creatinine blood levels. High creatinine blood levels can indicate serious kidney damage or disease. Kidney damage can be caused by a life-threatening infection, shock, cancer, or reduced blood flow to the kidneys. Other conditions that can cause increased blood creatinine levels include blockage of the urinary tract (such as by a kidney stone), heart failure, dehydration, excessive blood loss that causes shock, gout, or muscle conditions (such as rhabdomyolysis, gigantism, acromegaly, myasthenia gravis, muscular dystrophy, polymyositis). Usually a high blood creatinine level means that the creatinine clearance value is below normal.  High creatinine clearance. High creatinine clearance values can be caused by strenuous exercise, muscle injury (especially crushing injuries), burns, carbon monoxide poisoning, hypothyroidism, and pregnancy.  High BUN-to-creatinine ratio. High BUN-to-creatinine ratios occur with sudden (acute) kidney failure, which may be caused by conditions such as shock or severe dehydration. An obstruction in the urinary tract (such as from a kidney stone) can cause an elevated BUN-to-creatinine ratio. A very high BUN-to- creatinine ratio may be caused by bleeding in the digestive tract or respiratory tract .Low values  Low blood creatinine levels. Low blood creatinine levels can indicate a decrease in muscle mass caused by a disease, such as muscular dystrophy, or by aging. Low levels can also indicate some types
    • of severe liver disease or a diet very low in protein. Pregnancy can also cause low blood creatinine levels.  Low creatinine clearance. Low creatinine clearance results indicate serious kidney damage. Kidney damage can be due to conditions such as a life-threatening infection, shock, cancer, reduced blood flow to the kidneys, or urinary tract blockage. Other conditions, such as heart failure, dehydration, and liver disease (cirrhosis), can also cause low creatinine clearance results.  Low BUN-to-creatinine ratio A low BUN-to-creatinine ratio may be associated with a diet low in protein, a severe muscle injury called rhabdomyolysis, pregnancy, cirrhosis, or syndrome of inappropriate antidiuretic hormone secretion (SIADH). SIADH sometimes occurs with lung disease, cancer, diseases of the central nervous system, and the use of certain medications.What Affects the TestFactors that can interfere with your test and the accuracy of the results include the following:  Blood creatinine levels can be affected by several medications, including methyldopa (Aldomet), trimethoprim (Proloprim, Trimpex), vitamin C (ascorbic acid), cimetidine (Tagamet), some diuretics, and cephalosporin antibiotics, especially cefoxitin (Mefoxin).  Creatinine clearance results can be affected by some medications, including vitamin C (ascorbic acid), phenytoin (Dilantin), some cephalosporin antibiotics, captopril, aminoglycosides (Garamycin), trimethoprim (Proloprim, Trimpex), cimetidine (Tagamet), quinine, quinidine (Cardioquin, Quinaglute, Quinidex), procainamide (Procan, Pronestyl), and the antifungal medication amphotericin B.  BUN-to-creatinine ratio results can be affected by several medications, including cimetidine (Tagamet), steroids, and tetracycline antibiotics.  Strenuous exercise should be avoided 48 hours prior to a creatinine clearance test.  Eating large amounts [more than 8 oz(227 g)] of meat, especially beef, in the 24 hours prior to and during a creatinine clearance test  Failing to collect exactly 24 hours of urine during a creatinine clearance testWhat To Think About  A high blood creatinine level is usually associated with a low creatinine clearance because creatinine in the blood is removed, or filtered, by the kidneys. If the kidneys are not able to filter creatinine properly from the blood (low creatinine clearance), levels of creatinine in the blood increase (high blood creatinine level).  The amount of creatinine in amniotic fluid can be measured to estimate the maturity of a baby (fetus) and its ability to breathe if delivered. A baby with mature kidneys (and equally mature lungs) will produce more creatinine than an immature baby.  A normal blood creatinine level does not rule out kidney disease. To help determine whether kidney damage may be present, a BUN level is also measured. Other tests may also need to be done to evaluate kidney disease. For more information, see the medical test Blood Urea Nitrogen.  Creatinine levels increase more slowly than blood urea nitrogen (BUN) levels, so an increase in creatinine usually indicates chronic kidney problems.  The amount of creatinine in the blood depends partly on the amount of muscle tissue; therefore, blood creatinine levels are generally higher in men than in women. Also, people who have large muscles, such as athletes, normally have above-average blood creatinine levels.  A one-time urine sample to measure urine creatinine and sodium is sometimes done along with blood creatinine and sodium levels to help calculate a result called the fractional excretion of sodium (FENA). This test can help your health professional determine whether a problem with blood flow to the kidneys is caused by dehydration or shock versus damage to the kidneys themselves.
    • Creatinine, SerumMeasurement of serum creatinine is the most widely used measure of renal function. The diagnosticusefulness of serum creatinine as an indicator of glomerular filtration rate (GFR) is based upon itsconstant production from muscle creatine and its relatively constant renal excretion rate. About 1 to 2%of the creatine in muscle is converted to creatinine daily (15 to 30 mg creatinine per kg body weight).The amount of creatinine formed is proportional to muscle mass. Creatinine is removed from plasma byglomerular filtration and then excreted in the urine without significant tubular reabsorption.Serum creatinine is a crude indicator of renal disease. Moderate changes in GFR may not be detected byserum creatinine levels. A change in serum creatinine from 0.6 to1.2 mg/dL reflects a 50% decline inGFR, even though creatinine is still within the normal range. If a previous baseline creatinine is notavailable for comparison, a serum creatinine level of 1.2 mg/dL might be considered clinicallyinsignificant.Serum creatinine is decreased in individuals with small stature, cachexia, amputations, or muscledisease. Advanced liver disease causes low serum creatinine because of decreased hepatic conversion ofcreatine to creatinine, decreased dietary protein intake, muscle wasting, and increased renal tubularsecretion of creatinine. Patients with liver disease may have a normal serum creatinine even thoughcreatinine clearance is less than 60 mL/min. Elderly patients have decreased muscle mass anddecreased creatinine production. Creatinine levels are reduced during pregnancy because of increasedGFR.Acute renal failure (ARF) is a sudden loss of renal function occurring over several hours to days. Anincreased serum creatinine concentration, accumulation of nitrogenous wastes and a decline in urinaryoutput are the hallmarks of ARF. An increase of serum creatinine level by more than 0.5 mg/dL, a 50%increase of serum creatinine over a baseline level, or a >25% decline in creatinine clearance areaccepted indicators of ARF.Serum creatinine is increased when GFR is decreased. Causes of high creatinine levels include intrinsicrenal disease, urinary tract obstruction, and reduced renal blood flow from congestive heart failure,shock or dehydration. In acute renal failure, serum creatinine will rise 1 to 2 mg/dL per day. If the rateof rise is less, residual renal function exists. If the rate of rise exceeds 3 mg/dL per day, skeletal muscleor increased catabolism is also present. Rhabdomyolysis can cause a sudden increase in serumcreatinine. In patients with reduced renal blood, creatinine rises more slowly than BUN.Creatinine clearance can be estimated from the serum creatinine using the following formulas (weight isexpressed in kg, age in years, and serum creatinine in mg/dL):Creatinine clearance (male) = weight x (140 - age) 72 x serum creatinineCreatinine clearance (female) = weight x (140 - age) x 0.85 72 X serum creatinineThe ratio of BUN to creatinine can be used to determine the etiology of acute renal failure. Normally, theratio is 10 to 1. The ratio usually exceeds 20 in prerenal failure due to decreased renal perfusion, suchas occurs with hypertension, hemorrhage, or dehydration. Postrenal diseases, such as urinary tractobstruction, also increase the ratio between 10 and 20. It is normal (10 to12) in intrinsic renal diseasebecause BUN and creatinine rise proportionately. The clinical usefulness of this ratio is limited bynonrenal factors that increase BUN such as; GI bleed, parenteral nutrition, and glucocorticoid therapy.GI bleed increases BUN more than creatinine because of increased amino acid absorption from digested
    • blood and hypovolemia.In 2008, the National Kidney Disease Education Program (NKDEP), in collaboration with the InternationalFederation of Clinical Chemistry and Laboratory Medicine (IFCC) and the European CommunitiesConfederation of Clinical Chemistry (EC4), launched the Creatinine Standardization Program to reduceinter-laboratory variation in creatinine assay calibration and provide more accurate estimates ofglomerular filtration rate (eGFR).Previous laboratory methods for serum creatinine had a small, but somewhat variable, positive bias dueto interfering substances in normal serum. Consequently, better inter-laboratory standardization ofserum creatinine was necessary to promote standardization of eGFR and its use in clinical guidelines forkidney disease.To support this initiative, all manufacturers of instruments and reagents for measurement of serum orplasma creatinine began supplying reagents that have been re-calibrated to an isotope dilution massspectrometry (IDMS) reference method in 2008. With the Beckman Coulter reagents, this change causedcreatinine results less than 4.0 to decrease by 0.1-0.2 mg/dL, while creatinine results higher than 4.0increased by 0.2-0.4 mg/dL. Creatinine clearance calculated from serum and urine measurements werenot significantly affected by the recalibration of creatinine.As a result of this change, the lower end of the reference range for serum creatinine performed on aBeckman Coulter Dxc 600 instrument became slightly lower. Gender Old Range New Range Male 0.9 - 1.3 0.6 - 1.3 Female 0.6 - 1.1 0.4 - 1.1The original equation to estimate GFR was developed from the Modification of Diet in Renal Disease(MDRD) Study using the older creatinine methods with a slight positive bias. The new version of theMDRD equation has incorporated different coefficients for the IDMS calibrated serum creatinine method.For most patients, an eGFR using the MDRD Study equation is more accurate than a creatinine clearancecalculated from serum and urine measurements. Therefore, NKDEP recommends not performing ameasured creatinine clearance procedure for adults except when the patients basal creatinineproduction is very abnormal. This may be the case with patients of extreme body size or muscle mass(e.g., obese, severely malnourished, amputees, paraplegics or other muscle-wasting diseases) or withunusual dietary intake (e.g., vegetarian, creatinine supplements). Creatinine measurements at the lowvalues usually observed in pediatric patients have greater variability than for values seen in adults.Estimates of kidney function based on these values will exhibit greater variability than seen in adults.Reference range for urine creatinine is:Male 0.8 - 2.0 g/24 hourFemale 0.6 - 1.8 g/24 hourSpecimen requirement is one SST tube of blood
    • Creatinine ClearanceClearance of endogenous creatinine is the most practical test of renal function. Decreased renal bloodflow results in decreased clearance. Urine is collected for 24 hours and a blood sample is collected duringthis collection interval. Serum and urine creatinine levels are measured and the creatinine clearancecalculated using the following formula:(Urine creatinine x urine volume) / (Serum creatinine x min. of duration) = (mL) / (min)This value is then corrected for body surface area:Creatinine Clearance = ((mL) / (min)) x ((1.73 m2) / (Patients surface area (m2)))The accuracy of the creatinine clearance calculation depends on the accuracy of the urine collection.Twenty four-hour urine collections are considered optimal because they account for diurnal variation increatinine clearance. The laboratory has added "grams of creatinine per 24 hours" to the creatinineclearance report. This calculation is valuable in determining if a 24-hour urine collection is complete.Creatinine values < 1g/24 hours for men or < 0.9g/24 hours for women nearly always mean that theurine collection was incomplete. Normal urine volume is 0.6 to 2.0 liters per day, but most peopleproduce between 1.0 and 1.5 liters per day.Creatinine excretion increases with muscle mass, is lower among women and decreases with age.Nomograms are available to determine a patients age adjusted creatinine clearance percentile rank. Menusually excrete 19 to 26 mg of creatinine per kg of body weight daily and women usually excrete 14 to21 mg/kg body weight. The normal range is 1 -2 g per 24 hours for men and 0.6 - 1.5 g per 24 hoursfor women. Avoidance of exercise and adequate hydration are important factors in ensuring accurateresults.Renal failure causes reduced creatinine clearance. Creatinine clearance values of 30 to 40 mL/min/1.73M2 suggest moderate renal impairment, while values < 28 suggest severe impairment.Creatinine clearance may not be accurate in the following medical conditions. Over Estimated Under Estimated Cirrhosis Body building Muscle wasting Anabolic steroids Malnutrition High protein diet Vegetarian diet Congestive heart failure Obesity Dehydration EdemaReference range is 60 180 mL/min/1.73M2
    • Specimen requirement is a twenty four hour urine collection in a container without preservative. Instructthe patient to void in the morning and discard the specimen. All urine is then collected for the next 24hours, including the next first morning void. The container should be refrigerated during and after thecollection. Patients height and weight are needed for calculating the clearance. One SST tube of blood isalso required for measurement of serum creatinine. Blood Urea Nitrogen (BUN) Test OverviewA blood urea nitrogen (BUN) test measures the amount of nitrogen in your blood that comes from the waste producturea. Urea is formed when protein is broken down in your body. It is produced in the liver and eliminated from yourbody in urine.A BUN test is done to estimate how well your kidneys are functioning. If your kidneys are not able to remove ureafrom the blood normally, your BUN level increases. Heart failure, dehydration, or a diet high in protein can also increaseyour BUN level. Liver disease or damage can decrease your BUN level, because urea is made in the liver. A decreasedBUN level can occur normally in the second or third trimester of pregnancy.Blood urea nitrogen to creatinine ratio (BUN:creatinine)A BUN test may be done with a blood creatinine test. The level of creatinine in your blood also provides information onhow well your kidneys are working; a high creatinine level may mean your kidneys are not working properly. Themeasured blood urea nitrogen (BUN) and creatinine tests can be used to calculate the BUN-to-creatinine ratio(BUN:creatinine). A BUN-to-creatinine ratio can help your health professional predict which conditions, such asdehydration, may be causing abnormal BUN and creatinine levels and decreased kidney function.Why It Is DoneA blood urea nitrogen (BUN) test is done to:  Determine whether your kidneys are functioning normally.  Determine whether your kidney disease is getting worse.  Monitor treatment of your kidney disease.  Determine whether severe dehydration is present. A BUN-to-creatinine ratio may help your health professional determine whether decreased kidney function is the result of dehydration or kidney disease. Dehydration usually causes BUN levels to rise more than creatinine levels, resulting in an increased BUN-to-creatinine ratio. Kidney disease or blockage of the flow of urine from your kidney usually causes both BUN and creatinine levels to increase equally, resulting in a BUN-to-creatinine ratio that is normal.How To PrepareIf possible, avoid eating a diet high in meat or other protein before having a blood urea nitrogen (BUN) test.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.
    • How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain felt depends on the skill ofthe health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksRisks of a blood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsA blood urea nitrogen (BUN) test measures the amount of nitrogen in your blood that comes from the waste producturea.NormalNormal values may vary from lab to lab. Blood urea nitrogen (BUN) Normal 8–20 milligrams per deciliter (mg/dL) BUN-to-creatinine ratio Over 12 months of age: 10:1–20:1 Infants less than 12 months of age: Up to 30:1High values  A high BUN value can indicate kidney injury or disease. Damage can be caused by a variety of conditions, such as diabetes or high blood pressure, that directly affect the kidneys. In addition to direct damage to the kidneys, high BUN levels can be caused by blockage of the urinary tract (by an object such as a kidney stone or tumor) or reduced blood flow to the kidneys caused by dehydration or heart failure.  A high BUN can be caused by medications, such as allopurinol (Alloprin), aminoglycosides (Garamycin), furosemide (Lasix), indomethacin (Indocin), methotrexate (MTX), aspirin, amphotericin B, carbamazepine (Tegretol), vancomycin (Vancocin), propranolol (Inderal), rifampin (Rifadin), spironolactone (Aldactone), tetracyclines, thiazide diuretics, and triamterene (Dyrenium).  A high BUN value may also be caused by a high-protein diet, Addisons disease, tissue damage (such as from severe burns), or from bleeding in the gastrointestinal tract.  A rise in BUN can indicate kidney problems caused by diabetes.  High BUN-to-creatinine ratios occur with sudden (acute) kidney failure, which may be caused by conditions such as shock or severe dehydration. An obstruction in the urinary tract (such as from a kidney stone) can cause an elevated BUN-to-creatinine ratio. A very high BUN-to-creatinine ratio may be caused by bleeding in the digestive tract or respiratory tract .
    • Low values  A low BUN value may be caused by a diet very low in protein, malnutrition, or severe liver damage.  Drinking excessive amounts of liquid may cause overhydration and lead to a low BUN value.  BUN levels may normally be low in the third trimester of pregnancy.  A low BUN-to-creatinine ratio may be associated with a diet low in protein, a severe muscle injury called rhabdomyolysis, pregnancy, cirrhosis, or syndrome of inappropriate antidiuretic hormone secretion (SIADH). SIADH sometimes occurs with lung disease, cancer, diseases of the central nervous system, and the use of certain medications.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Medications, such as amphotericin B (such as Fungizone), nafcillin, aminoglycosides (such as Garamycin), kanamycin (Kantrex), and tobramycin (Nebcin), corticosteroids, tetracycline antibiotics, and rarely, the antibiotic chloramphenicol (Chloromycetin).  Taking diuretics, which can result in dehydration.  Your age. BUN levels gradually increase with age.  Your sex. Women and children may have lower BUN levels than men.What To Think About  A BUN test may be done with a blood creatinine test. The measured blood urea nitrogen (BUN) and creatinine tests can be used to calculate the BUN-to-creatinine ratio (BUN:creatinine). For more information, see the medical test Creatinine and Creatinine Clearance.  BUN levels may be measured regularly in people who are undergoing kidney dialysis. BUN levels are used to help determine the frequency and intensity of dialysis therapy.
    • Blood Urea Nitrogen (BUN)Urea is the major end product of protein and amino acid catabolism and is produced in the liver in theurea cycle. Urea is easily diffusible and exists in all body fluids in practically the same concentration.Urea is filtered freely by the glomeruli and reabsorbed by the proximal and distal tubules. BUNconcentration is primarily regulated by renal tubular reabsorption, which is highly dependent on urineflow rate. Increased tubular flow, due to blood volume expansion, decreases absorption and BUNconcentration. Decreased tubular flow, due to volume depletion or congestive heart failure, increasesabsorption and BUN concentration. BUN concentration is also affected by protein intake (malnutrition orhyperalimentation), endogenous protein metabolism, and liver disease. These variables make BUN arather poor measure of renal function.Most clinicians agree that creatinine is a more specific indicator of glomerular function than BUN.However, the BUN to creatinine ratio may be used as an indirect estimate of renal function. It iscommonly used to determine the etiology of acute renal failure. The ratio of BUN to creatinine can beused to determine the etiology of acute renal failure. Normally, the ratio is 10 to 1. The ratio usuallyexceeds 20 in prerenal failure due to decreased renal perfusion, such as occurs with hypertension,hemorrhage, or dehydration. It is normal in intrinsic renal disease because BUN and creatinine riseproportionately. Postrenal diseases, such as urinary tract obstruction, also increase the ratio above 10.The clinical usefulness of this ratio is limited by nonrenal factors that increase BUN such as GI bleed,parenteral nutrition, and glucocorticoid therapy. A GI bleed increases BUN more than creatinine becauseof the increased amino acid absorption from digested blood and hypovolemia.Several diseases may cause a decreased BUN to creatinine ratio of less than 8 to 1. Rhabdomyolysisresults in increased production of creatinine. Liver disease and malnutrition can decrease the productionof urea. Hemodialysis and peritoneal dialysis remove urea more efficiently than creatinine. Somemedications may elevate serum creatinine by blocking tubular secretion. The most common examplesare cimetidine, trimethoprim, and pyrimethamine.BUN concentration can be used in patients with chronic renal failure to determine the timing of dialysis.BUN correlates with uremic symptoms better than serum creatinine concentration. BUN levels fall morerapidly than creatinine following dialysis and can be used to assess the adequacy of dialysis.In summary, increased BUN may be associated with renal failure, urinary tract obstruction, dehydrationand gastrointestinal hemorrhage. Decreased BUN may be associated with hepatic failure and decreasedprotein intake.Reference range is 5 - 20 mg/dL.Specimen requirement is one SST tube of blood. Hemolysis should be avoided.
    • Ammonia Test OverviewAn ammonia test measures the amount of ammonia in the blood. Most ammonia in the body forms when protein isbroken down by bacteria in the intestines. The liver normally converts ammonia into urea, which is then eliminated inurine.Ammonia levels in the blood rise when the liver is not able to convert ammonia to urea. This may be caused by cirrhosisor severe hepatitis.Why It Is DoneAn ammonia test is done to:  Check how well the liver is working, especially when symptoms of confusion, excessive sleepiness, coma, or hand tremor are present.  Check the success of treatment for severe liver disease, such as cirrhosis.  Help identify a childhood disorder called Reyes syndrome that can damage the liver and the brain. Ammonia testing can also help predict the outcome (prognosis) of a diagnosed case of Reyes syndrome.  Help predict the outcome (prognosis) of a diagnosed case of acute liver failure.  Check the level of ammonia in a person receiving high-calorie intravenous (IV) nutrition (hyperalimentation).How To PrepareDo not eat, drink anything other than water, or smoke for 8 hours before having an ammonia blood test.Avoid strenuous exercise just prior to having this test.Tell your doctor if you:  Are taking any medicines. Many medicines can interfere with test results. Your health professional may instruct you to stop taking certain medicines for several days before having an ammonia test.  Smoke or drink alcohol.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results may mean. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneThe health professional taking a sample of your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Put a gauze pad or cotton ball over the needle site as the needle is removed.  Put pressure on the site and then put on a bandage.
    • How It FeelsThe blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight.You may feel nothing at all from the needle, or you may feel a quick sting or pinch.RisksThere is very little chance of a problem from having blood sample taken from a vein.  You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.  In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.  Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.ResultsAn ammonia test measures the amount of ammonia in the blood. Results are usually available within 12 hours.NormalNormal values may vary from lab to lab. AmmoniaAdults: 15–45 micrograms per deciliter (µg/dL) 11–32 micromoles per liter (µmol/L)Children: 40–80 µg/dL 28–57 µmol/LNewborns: 90–150 µg/dL 64–107 µmol/LHigh valuesHigh levels of ammonia in the blood may be caused by:  Liver disease, such as cirrhosis or hepatitis.  Reyes syndrome.  Heart failure.  Kidney failure.  Severe bleeding from the stomach or intestines.High ammonia values in a baby may be present when the blood types of a mother and her baby do not match(hemolytic disease of the newborn).What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  Smoking.  Severe constipation.  Eating a high-protein or a low-protein diet.  Using medicines that increase blood ammonia levels, such as heparin, some diuretics (such as furosemide), acetazolamide, and valproic acid.  Using medicines that decrease ammonia levels, such as neomycin, tetracycline, diphenhydramine, isocarboxazid (Marplan), phenelzine (Nardil), and tranylcypromine (Parnate), heparin, and lactulose.  Strenuous exercise just before the test.What To Think About  Ammonia levels do not always reflect the severity of a persons symptoms. For example, a person with severe cirrhosis may have only slightly elevated blood ammonia levels and yet may not be thinking clearly or may be sleepy or in a coma. Other people with very high ammonia levels may think and act normally.
    •  Symptoms of a high ammonia level, such as confusion or extreme sleepiness, may be treated with a medicine called lactulose, a laxative that works by reducing ammonia production in the intestines.  It is common for newborns to have slightly high levels of ammonia in their blood; however, the levels are temporary and usually do not cause symptoms. AmmoniaAmmonia is produced in the gastrointestinal tract by the action of bacterial enzymes on proteins andamino acids. It enters the portal circulation and is normally metabolized in the liver to urea andglutamine. When the liver is unable to perform this function, increased amounts of ammonia enter thearterial circulation and diffuse across the blood-brain barrier. Helicobacter pylori in the stomach appearto be an important source of ammonia in patients with cirrhosis.The use of ammonia for monitoring patients with hepatic encephalopathy is controversial. It is unlikelythat ammonia is solely responsible for the encephalopathy of hepatic insufficiency. Plasma ammonialevels have usually been found to correlate poorly with the clinical stage of hepatic encephalopathy. Anormal level does not rule out early stage hepatic encephalopathy. Measuring plasma ammonia may beuseful in suggesting a hepatic origin for an encephalopathy of unknown origin. It is not useful in patientswith known liver disease.Elevated levels are also seen in:  Reyes syndrome and other urea cycle enzyme deficiencies  Acute leukemia  Bone marrow transplantation  Blood transfusion  Portal-systemic shunts  Gastrointestinal bleeding  Chronic renal failureMany factors can affect ammonia levels:  Arterial levels are 20 - 30 umol/L higher than venous in patients with hepatic insufficiency  Arteriovenous difference is zero in normal individuals at rest  Tourniquet use during venipuncture increases ammonia levels  High protein intake increases ammonia levels  Exercise increases ammonia up to threefold (produced by muscle)  Smoking 1 cigarette increases ammonia by 10 umol/L  Delay in separation of plasma from RBCs increases ammonia by 20% in 1 hour and 100% in 2 hours  Valproic acid increases ammonia production  Irrigation fluids containing glycine increase ammonia productionReference range is 10 - 40 umol/L.Ideally, arterial, rather than venous, specimens should be collected. Specimen requirement is onesodium or lithium heparin green top tube. Blood should be drawn without a tourniquet and then placedin ice for immediate transport to the lab. The tube should be full and must be kept tightly stoppered. Itshould be centrifuged immediately and the plasma separated into a screw top plastic vial. If the vialcannot be delivered to the lab immediately, it should be frozen at -70 C.
    • Kidney Biopsy Test OverviewA percutaneous kidney biopsy is done by inserting a long needle through the back (flank) to remove a sample of kidneytissue. The tissue sample can then be sent to a laboratory and examined under a microscope to help a doctordetermine the condition of the kidney and look for signs of infection or other diseases.The two kidneys are located on either side of the spine, in the lower back. They help regulate the balance of water,salts, and minerals in the blood. The kidneys also filter waste products from the blood to form urine.A kidney biopsy may be done to evaluate suspected kidney problems or abnormal results from kidney function tests,such as blood and urine tests, ultrasound, or a computed tomography (CT) scan. If kidney cancer is suspected, a biopsymay not be done because of the possible risk of spreading the cancer.Why It Is DoneA kidney biopsy is done to:  Diagnose kidney disease when there is unexplained, persistent blood or protein in the urine or when there is reduced kidney function, as determined by kidney function tests.  Diagnose kidney abnormalities seen on an ultrasound or a CT scan.  Monitor kidney disease and evaluate the effectiveness of treatment.  Evaluate a transplanted kidney for evidence of rejection.How To PrepareTell your doctor if you:  Are taking aspirin, nonsteroidal anti-inflammatory medications (NSAIDs, such as ibuprofen or naproxen), or blood thinners (such as Coumadin or heparin). Your doctor may instruct you to stop taking aspirin or NSAIDs for several days before this test.  Are allergic to any medications, including anesthetics.  Have had any bleeding problems.  Are or might be pregnant.Do not eat or drink for 8 hours before the test. You will empty your bladder before the test.For a kidney biopsy, you will be asked to sign a consent form. Talk to your health professional about any concerns youhave regarding the need for the test, its risks, how it will be done, or what the results will indicate. To help youunderstand the importance of this test, fill out the medical test information form (What is a PDF document?).Arrange for someone to drive you home after the test because you may be given a sedative to help you relax.You will have blood tests done before the kidney biopsy to see whether you have any bleeding problems or bloodclotting disorders. You may also have an ultrasound test or CT scan of the kidney to help determine the best place inyour kidney to insert the biopsy needle.How It Is DoneA kidney biopsy is done by a urologist, nephrologist, or a radiologist in a clinic or a hospital. A kidney biopsy isfrequently done by a radiologist using ultrasound, a CT scan, or magnetic resonance imaging (MRI) to help guide thebiopsy needle.
    • You will need to take off all or most of your clothes, and you will be given a cloth or paper covering to use during thetest. Before the test, you may be given a sedative through an intravenous (IV) line in your arm or hand. The sedative willhelp you relax and remain still.You will be asked to lie facedown on a firm surface. A sandbag, a firm pillow, or a rolled towel will be placed under yourbody to support your abdomen. Be sure you make yourself as comfortable as possible so you can remain still during thebiopsy. It is particularly important that you follow your doctors directions about breathing and keeping still while the testis being performed.Your doctor will examine your back and may mark the biopsy site by making a slight indentation in your skin with apencil or blunt instrument. The biopsy may be done on either the right or the left kidney. The site will be cleaned with anantiseptic solution and draped with sterile towels. Your doctor will then inject a local anesthetic to numb the area wherethe biopsy needle will be inserted.Your doctor will then insert a biopsy needle through the skin while looking at your kidney with ultrasound. You will beasked to hold your breath and stay very still while the needle is inserted into the kidney.The needle is removed after the tissue sample is taken and pressure is held on the biopsy site for several minutes tostop the bleeding. After a few minutes of pressure on the biopsy site, a bandage is applied. The entire procedure usuallytakes about 15 to 30 minutes.After the test, you will rest in bed for 6 to 24 hours. Your pulse, blood pressure, and temperature will be checked atregular intervals after the biopsy.If no complications develop, you will be allowed to go home. To prevent bleeding at the biopsy site, lie flat on your backfor the next 12 to 24 hours. You may resume your regular diet, but you should avoid taking aspirin or anti-inflammatorymedications for a week after the biopsy. You may also resume your regular activities, but you should avoid strenuousactivities (such as heavy lifting, hard running, motorcycle riding, contact sports, or other activities that might jar or joltyour kidney) for 2 weeks after the test. Also, drink extra fluids to avoid dehydration.How It FeelsWhen the local anesthetic is injected, you may feel a brief stinging or burning pain. When the biopsy needle is inserted,you will again feel a sharp pain for a few seconds, similar to having your blood drawn.It is normal to feel mild muscle soreness in the area of the biopsy for 2 to 3 days after the procedure. It is also normal toexperience a small amount of bleeding through the bandage after the procedure. Talk to your doctor about how muchdiscomfort and bleeding can be expected. Many people will have bright red blood in their urine for the first 24 hours afterthis test; this is expected.RisksSerious complications resulting from a kidney biopsy are rare. Risks include:  Bleeding into the muscle, which can cause soreness.  Bleeding into the kidney. In fewer than 1 in 1,000 people, injury caused by the biopsy results in the loss of the kidney.  Infection of the skin at the biopsy site.  Pneumothorax (collapsed lung).  Puncturing a major blood vessel, which may require blood transfusions or surgery. This is very rare.  Death. This also is extremely rare.After the testAfter the test, call 911 or other emergency services immediately if you develop:  Signs of shock.  Severe pain in your chest, shoulder, or abdomen.  Moderate to severe difficulty breathing.After the test, call your doctor immediately if you:  Have increasing pain in your back, abdomen, or groin.
    •  Have excessive bleeding or drainage (such as pus) from the site where the biopsy sample was taken.  Have blood in your urine for longer than 24 hours after the test.  Develop increasing tenderness or pain at the site where the biopsy sample was taken.  Develop a fever.  Have weakness or lightheadedness when changing position, such as rising from sitting or lying to standing.ResultsA percutaneous kidney biopsy is done by inserting a long needle through the back (flank) to remove a sample of kidneytissue. The tissue sample can then be sent to a laboratory and examined under a microscope to help a doctordetermine the condition of the kidney.  Samples of kidney tissue are usually sent to a pathology lab, where they will be examined under a microscope for evidence of kidney diseases such as kidney cancer.  Other samples of kidney tissue may be sent to a microbiology lab to determine whether an infection is present.Test results are usually available in 2 to 4 days. If tests are done to detect infections, it may take several weeks forresults to come back. Kidney biopsyNormal: The structure and cells of the kidney appear normal. There are no signs of inflammation, scar tissue, infection, or cancer.Abnormal: The sample may show signs of scarring due to infection, poor blood flow (perhaps resulting from a blood clot in a renal vein), glomerulonephritis, a kidney infection (pyelonephritis), or signs of other diseases that can affect more than one part of the body (such as systemic lupus erythematosus). Kidney tissue can also show evidence of certain malignant tumors, such as Wilms tumor (which occurs in early childhood) and renal cell cancer (which is most common after age 40).What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Having an untreated bleeding or blood clotting disorder.  The inability to remain still.  Having advanced kidney disease, uncontrolled high blood pressure, or only one kidney.  Obesity.  Having a severely deformed spine.  Having a urinary tract infection.  A chance that a cancerous growth may be missed because a needle biopsy collects tissue from such a small area.  Insufficient tissue sample. Test results may be inconclusive if the biopsy sample does not contain enough tissue to make a definite diagnosis.What To Think About  A kidney biopsy should be done only after other less-invasive tests for kidney disease (including blood and urine tests, ultrasound, and a CT scan) have failed to diagnose a kidney problem clearly or define its severity. A kidney biopsy has both more risk than these other tests and a high rate of false-negative results. About 20% to 30% of the time, the results of a kidney biopsy are inconclusive and a repeat biopsy is needed. For more information, see the medical tests Abdominal Ultrasound and CT Scan of the Body.  A kidney biopsy will not be done if kidney cancer is suspected. Surgery to remove the kidney will most likely be recommended in this situation.  Open kidney biopsy and brush biopsy are two other methods that may be used to obtain kidney tissue samples. These methods require an overnight stay in the hospital. o An open kidney biopsy is a surgical procedure performed in an operating room under general anesthesia. An incision is made through the back or the side and a small wedge of kidney tissue is removed. Open biopsy is the preferred method when a tumor is suspected. It may also be done when a person has only one functioning kidney, to reduce the chance of
    • injuring the remaining kidney. The risks of having general anesthetic and surgery must be considered.o A brush biopsy of the urinary tract is a procedure done under general, local, or spinal anesthesia to determine whether a suspicious mass seen inside the lower part of the kidney (renal pelvis ) or ureter is cancerous (malignant). It requires the use of a special dye (contrast material) that makes structures more visible on the X-ray film. First, the contrast material is instilled through a catheter inserted into the ureter. X-rays are taken to help guide the doctor as the catheter is advanced up the ureter to a point inside the kidney where the biopsy sample will be taken. A nylon or steel brush is then passed through the catheter to brush the inside of the kidney and collect tissue samples. This procedure is repeated at least six times, using a new brush each time. Complications from this high-risk test include perforation of the ureter or kidney, bleeding, leaking of the contrast material into surrounding tissues, and infection. It should not be done on someone who is allergic to iodine or iodine dyes or who has a urinary tract infection or an obstruction at or below the biopsy site. Brush biopsy is being replaced by ureteroscopy with a biopsy in many medical centers.o Ureteroscopy with a biopsy is preferred for sampling a suspicious mass in the renal pelvis or ureter. Ureteroscopy is a surgical procedure performed in an operating room under spinal or general anesthesia. It requires the use of an instrument (ureteroscope) to view the inside of the ureter and lower part of the kidney (renal pelvis). Once the mass is located, a biopsy is obtained through the ureteroscope.
    • Kidney Stone Analysis Test OverviewKidney stone analysis is a test done on a kidney stone to determine its chemical makeup. The test is done on a kidneystone that has been passed in the urine or removed from the urinary tract during surgery. Chemical analysis of a kidneystone can help identify the type of stone and can provide important clues about why it formed. Kidney stone analysismay also guide treatment and provide information that may prevent stones from forming in the future. People who havehad a kidney stone are at risk for having another one, so prevention measures are important.A kidney stone (renal calculus) forms in the kidney from substances that separate out of the urine. See an illustration ofa kidney stone .A kidney stone may range from the size of a grain of sand to about 1 in.(2.5 cm) or larger across. Sometimes a stonemay leave the kidney and move down a ureter into the bladder. From the bladder, the stone passes through the urethraand out of the body in urine. See an illustration of the urinary tract . Passing a kidney stone through a ureter or theurethra may be painless or may cause severe pain. A kidney stone may cause other symptoms, such as blood in theurine (hematuria), painful urination, or urgency to urinate.Why It Is DoneA kidney stone analysis is done to:  Determine the chemical makeup of a kidney stone.  Guide treatment for a kidney stone.  Provide information on how to prevent future formation of a kidney stone.How To PrepareIf you suspect you might have a kidney stone, ask your health professional whether you need an evaluation. He or shemay have you collect the stone by straining your urine through a fine-mesh strainer or through fine gauze. Your healthprofessional may give you a kidney stone strainer, or you may purchase one from a medical supply store. Straining thefirst urine specimen of the morning is especially important, because a stone may pass into your bladder during the night.Examine the strainer for a kidney stone, which may look like a grain of sand or a small piece of gravel. Any stone youfind should be kept dry (not in contact with liquid, such as urine). Seal it in a vial or a plastic bag and take it to yourhealth professionals office or lab for analysis. Do not apply tape to the kidney stone because doing so can interfere withthe results of the kidney stone analysis.Talk to your health professional about any concerns you have regarding the need for the test, its risks, or how it will bedone. To help you understand the importance of this test, fill out the medical test information form (What is a PDFdocument?).How It Is DoneThe kidney stone you take to the lab will be cleaned of any blood or tissue and then analyzed to determine its chemicalmakeup.How It FeelsThe most common way a kidney stone is collected for analysis is by passing it in urine. Passing a stone may bepainless or may be extremely painful. The pain usually begins suddenly and tends to come in waves. A sand-sized
    • stone may pass with little pain. A larger stone may cause intense pain in the lower back, groin, or genitals as it movesdown the ureters or out through the urethra.A small stone may pass without medical treatment. A large stone may require surgery or another type of procedure.RisksThere are no risks associated with kidney stone analysis. However, a kidney stone can:  Contain bacteria that can cause a urinary tract infection (UTI) or make an existing infection worse.  Damage the kidney, especially if the stone is a staghorn (struvite) stone.  Block the urinary tract. This usually occurs (to some degree) while the stone is passing.ResultsKidney stone analysis is a test done on a kidney stone to determine its chemical makeup.Knowing the type of kidney stone helps determine the best treatment option. Your health professional will discusstreatment and prevention measures with you. Kidney stone analysis  About 80% of kidney stones are made of calcium oxalate and/or calcium phosphate.  Up to 10% of kidney stones are made of magnesium ammonium phosphate (struvite).  About 10% of kidney stones are made of uric acid.  Less than 1% of kidney stones are made of a chemical called cystine.What Affects the TestApplying tape to secure a kidney stone while transferring it to a lab may interfere with the results of a kidney stoneanalysis.What To Think About  About 90% of kidney stones can be seen on regular X-rays.  Currently, a computed tomography (CT) scan of the ureters and kidneys (also called a CT urogram) is the preferred method to diagnose kidney stones. For more information, see the medical test CT Scan of the Body.  Ultrasound may also be used to help detect kidney stones. For more information, see the medical test Abdominal Ultrasound.  Another test that can be done to locate a kidney stone is intravenous pyelogram (IVP). During IVP, a dye is injected into a vein. As the dye travels to the kidneys, X-rays are taken to track the movement of the dye. For more information, see the medical test Intravenous Pyelogram (IVP).  Although most kidney stones contain calcium, a low-calcium diet does not usually prevent stones from forming. For more information on reducing your risk for a kidney stone, see the topic Kidney Stones.  Knowing the type of kidney stone helps determine the best treatment option.
    • Medical history and physical exam for kidney stones Exam OverviewYour first diagnosis of kidney stones often occurs when you are in great pain. Your doctor will ask a few questions andexamine you before suggesting treatment.After you pass a stone, your doctor may give you another exam to find out if you are likely to have more stones in thefuture.All or some of the following questions may be asked at your initial and follow-up exams.Lifestyle questions  How much fluid do you drink? Do you drink a lot of water or soft drinks? Not getting enough fluids (dehydration) is the most common cause of kidney stones. Drinking a lot of "fizzy" soft drinks may make kidney stones more likely.  How active are you? Do you get a lot of exercise or play sports? Do you have a job where you are active, or where you are sitting? People who are not physically active are more likely to develop kidney stones. If you do exercise and sweat a lot but do not drink fluids to replace the lost fluid, you may also be more likely to develop stones.  What types of foods do you eat? A diet that makes you more likely to develop stones includes: o Foods high in oxalates, such as dark green vegetables, chocolate, and beans. o Eating many foods that contain vitamin C or D, or supplements of these vitamins. o Foods that contain a lot of salt (sodium). o Foods or drinks that contain little calcium.Medicine and medical conditions  What medicines are you taking? Some medicines make it more likely that you will develop kidney stones.  What medical conditions have you had in the past or do you now have? Medical conditions that make it more likely you will develop kidney stones include: o Gout. o Frequent urinary tract infections (UTIs). o History of urinary system abnormalities. o A family history of kidney stones, gout, or parathyroid disease. o Inflammatory bowel disease. o Sarcoidosis. o Previous abdominal surgery. o Bed rest for a long period of time.Physical examDuring the physical exam, your doctor will examine your body for other clues that may explain the cause of yoursymptoms. He or she may:  Take your temperature.  Check your weight.  Press or tap on your abdomen (abdominal palpation) or back, to check for pain or fluid buildup.  Examine your groin, to check for enlarged lymph nodes.Why It Is Done
    • A complete medical history and physical exam will help your doctor find out if you currently have a kidney stone and ifyou are likely to have one again.ResultsYour answers to the lifestyle and medical questions will help your doctor find out if you currently have a kidney stoneand if you are likely to have one again.Physical symptoms that indicate that you may have a kidney stone include:  Intense pain in the side, abdomen, groin, or genitals.  Frequent and painful urination. A urinary tract infection may also be present.  Fever, especially if a urinary tract infection is also present.  Nausea and vomiting.  Profuse sweating (diaphoresis).What To Think AboutAlthough your doctor may decide you have kidney stones based on your medical history and physical exam, he or shemay also do lab tests such as a urinalysis or urine culture. Your doctor may start treatment before these tests are doneor you know the results.If you have a family history of kidney stones or pass more than one stone, your doctor may do more tests to find out thetype of stone.
    • Medical history and physical exam for urinary tract infections Exam OverviewIf you have symptoms of a urinary tract infection (UTI), your initial evaluation by your doctor will include a medicalhistory and physical exam. A medical history includes an evaluation of your current urinary tract symptoms, history ofurinary tract infections or other urinary tract problems, family health history, and sexual history. You and your doctor willdiscuss your general health and the results of previous testing.For women, your doctor will:  Evaluate the possibility of pregnancy and any history of reproductive problems.  Include a pelvic exam if symptoms indicate a possible pelvic infection or urethritis.  Examine your lower back, abdomen, and the area just above where the pelvic bone and the lower abdomen meet for tenderness, pain, or abnormalities.  Take your temperature.For men, your doctor will:  Evaluate any history of prostate problems.  Examine your genitals, lower back, and abdomen.  Examine your rectum and rectal area to check for prostate enlargement, growths, or inflammation.  Take your temperature.Why It Is DoneYou have symptoms of a UTI.ResultsFindings of the medical history and physical exam include the following:Normal  No pain, growths, or abnormalities  No prostate enlargement or tenderness (men only)  No discharge from the urethraAbnormal  Pain or discomfort in response to pressure on the lower back, abdomen, or the area above the pelvic bone  Growths or abnormalities detected during pelvic or rectal exam  Enlarged or tender prostate gland (men only)  Discharge from the urethraWhat To Think AboutA thorough medical history and physical exam can often help rule out other possible causes of your symptoms, such asa vaginal yeast infection, sexually transmitted disease, or prostatitis. Provide your doctor with as accurate a medical andsexual history as you can.
    • Medical history and physical examination for urinary incontinence in women Exam OverviewA medical history is the most important part of the examination for urinary incontinence. During the medical history, yourhealth professional will ask you to describe:  How long you have had incontinence.  What, if anything, you are doing (laughing, sneezing, coughing) when you experience incontinence.  How often you have the problem and how much urine you lose.  Risk factors you may have that could lead to incontinence.  Your eating habits.  Your bowel habits, to determine whether chronic constipation may be contributing to incontinence.  Prescription and nonprescription medications you take.  Treatments for previous problems affecting your urinary or reproductive tract.  Your use of pads or other protective devices to control urine leakage.The health professional will ask questions about your general health. To determine the cause of your incontinence, heor she will ask specific questions about your urinary and reproductive tracts, your intestines, and your nervous system.Symptoms and conditions that are often related to incontinence will also be investigated, such as:  A need to urinate frequently.  A sudden, strong urge to urinate.  Inability to urinate.  A blocked urine stream.  Leakage of urine while sleeping.  Possible urinary tract infection.A physical examination involves an abdominal, rectal, and pelvic examination. The examination includes:  Looking for growths, such as tumors, in the pelvic area.  Checking the pelvic muscle tone.  Checking that the bladder has not dropped out of its proper position and that it is not pressing on the vaginal wall.  Checking the nervous system to see if a problem is causing muscle weakness or loss of reflexes.Why It Is DoneA medical history and physical examination are done for everyone who sees a health professional about urinaryincontinence.ResultsNormal  No growths or physical abnormalities are found.  The pelvic organs (uterus and bladder) have not dropped from their normal position.  Pelvic muscle tone is firm.  No abnormal muscle weakness, or reflex loss is due to a nerve problem.  Constipation or a hard stool is not present.
    • Abnormal  Pain or discomfort occurs when the doctor presses on the back or abdomen. (This may suggest a urinary tract infection. Urinalysis and urine culture may be needed.)  Growths or abnormalities that may be blocking the urinary tract are detected during the pelvic or rectal examination. Ultrasound or computerized tomography (CT scan) may be recommended.  Pelvic muscle tone is weak, which may be a factor in stress incontinence. A bladder stress test or pad test may be needed. (For more information, see the Exams and Tests section of the topic Urinary Incontinence in Women.)  Other areas of the body, in addition to the urinary tract, show a loss of muscle control or signs of Parkinsons disease or stroke. Referral to a neurologist may be needed. (For more information, see the topic Parkinsons Disease or Stroke.)What To Think AboutThe medical history is important and can determine some causes of incontinence.Be certain to tell the health professional about all prescription and nonprescription medications you are taking.The physical examination can find structural abnormalities of the urinary tract that may be causing or contributing toincontinence. Findings from the physical examination help determine whether further testing is
    • Medical history and physical examination for lupus Exam OverviewA physical examination for suspected lupus (systemic lupus erythematosus, or SLE) includes a thorough check of yourskin, joints, lungs and breathing, nervous system, and heart.The medical history includes questions about:  Arthritis, joint, or muscle pain.  Weight loss or fatigue.  Skin rashes, especially after exposure to sunlight.  Sores in the mouth, nose, or other mucous membranes.  Chest pain.  Hair loss or thinning.  Seizures, convulsions, or other nervous system symptoms.  Whether anyone in your family has lupus.  Whether you have ever had kidney disease.Why It Is DoneA physical examination and medical history are done to evaluate symptoms. The parts of the body that are examined,and the questions that are asked, depend on which diseases your doctor suspects or considers most likely.ResultsYour doctor will use diagnostic criteria to distinguish lupus from other autoimmune and rheumatic diseases. You mayhave all of the lupus-related conditions at once or you may experience them over a period of time.Diagnostic criteria for systemic lupus erythematosus:  Butterfly (malar) rash on cheeks  Rash on face, arms, neck, torso (discoid rash)  Skin rashes that result from exposure to sunlight or ultraviolet light (photosensitivity)  Mouth or nasal ulcers, usually painless  Joint swelling, stiffness, pain involving 2 or more joints (arthritis)  Inflammation of the membranes surrounding the lungs (pleuritis) or heart (pericarditis)  Abnormalities in urine (test results show increased protein in the urine or clumps of red blood cells or kidney cells, called cell casts, in the urine)  Nervous system problems, such as seizures or psychosis, without known cause  Problems with the blood, such as reduced numbers of red blood cells (anemia), platelets, or white blood cells  Positive antinuclear antibody (ANA) test  Laboratory tests indicating increased autoimmunity (antibodies against normal tissue)If you have 4 or more of the 11 conditions listed above, your doctor is likely to diagnose lupus; 3 suggest that lupus isprobably present; and 2 raise the possibility of the disease. If you have 2 or 3 of the signs or symptoms, your doctor can 1perform laboratory tests that can help confirm whether you have lupus.What To Think AboutLupus is hard to diagnose because its symptoms are similar to those of many other disorders. A few nonspecificsymptoms may persist for years before other problems develop.
    • When classic lupus symptoms develop quickly, lupus can be more easily diagnosed. If the symptoms are nonspecific oroccur off and on, or if test results are inconclusive, it may take months or even years to make a definite diagnosis.Complete the medical test information form (PDF) (What is a PDF document?) to help you prepare for thistest.ReferencesCitations 1. Petri M (2001). Systemic lupus erythematosus: Clinical aspects. In WJ Koopman, ed., Arthritis and Allied Conditions: A Textbook of Rheumatology, 14th ed., vol. 2, pp. 1455–1479. Philadelphia: Lippincott Williams and Wilkins.
    • Medical history and physical exam for tuberculosis (TB) Exam OverviewWhen you give your medical history, your doctor collects information about whether you are likely to have tuberculosis(TB), a bacterial infection. An active infection can spread to other people. A latent infection cannot spread to otherpeople, but it can turn active and become contagious. Your doctor will ask whether you:  Have symptoms of TB, such as ongoing cough, fatigue, fever, or night sweats.  Have been in any situations that may increase your risk of being infected with TB-causing bacteria, such as living with a person who has active TB, traveling recently to places where TB is common, or having a weakened immune system.  Have had a tuberculin skin test before, and what the results were.  Have human immunodeficiency virus (HIV) infection or have had an HIV test in the past 6 months.  Are taking any medications, both prescription and nonprescription. Your doctor will want a list of all of these medications, including herbs and natural products.  Have been diagnosed with TB in the past but were not treated.The physical exam looks for signs of TB. A doctor uses a stethoscope to listen to your breathing for sounds that indicatea problem in your lungs. The doctor also will look for signs of a TB infection in other areas of your body (extrapulmonaryTB).Why It Is DoneA medical history and physical exam may be done to check for TB if you have:  TB symptoms (such as ongoing cough, fatigue, fever, or night sweats).  Close contact with a person infected with active TB disease.  Traveled in an area where TB is common.ResultsResults from the physical exam may include:NormalThe sounds your lungs make while you breathe are normal. There are no signs of TB infection outside the lungs(extrapulmonary TB).AbnormalThe sounds your lungs make while you breathe indicate a problem, or there are signs of TB infection outside the lungs,such as swollen lymph nodes.What To Think AboutWhile the medical history and physical exam can suggest you have active TB disease, finding TB-causing bacteria inthe mucus from your lungs (sputum) provides proof.The medical history alone does not prove whether you have TB disease outside the lungs (extrapulmonary TB). Havinga sample of the affected area (biopsy) examined in the lab for TB-causing bacteria will let you know for sure.
    • Helicobacter pylori Tests Test OverviewHelicobacter pylori tests are used to detect a Helicobacter pylori (H. pylori) infection in the stomach and upper part ofthe small intestine (duodenum). H. pylori can cause peptic ulcers; however, most people with H. pylori in their digestivesystems do not develop ulcers.Four tests are used to detect H. pylori:  Blood antibody test. A blood test checks to see whether your body has made antibodies to H. pylori bacteria. If you have antibodies to H. pylori in your blood, it means you either are currently infected or have been infected in the past.  Urea breath test. A urea breath test checks to see if you have H. pylori bacteria in your stomach. The breath test is not always available.  Stool antigen test. A stool antigen test checks to see if substances that trigger the immune system to fight an H. pylori infection (H. pyloriantigens) are present in your feces (stool). Stool antigen testing may be done to help support a diagnosis of H. pylori infection or to determine whether treatment for an H. pylori infection has been successful.  Stomach biopsy. A small sample (biopsy) is taken from the lining of your stomach and small intestine during an endoscopy. Several different tests may be done on the biopsy sample. For more information, see the medical test Upper Gastrointestinal Endoscopy.Why It Is DoneA Helicobacter pylori (H. pylori) test is done to:  Determine whether an infection with H. pylori bacteria may be causing an ulcer or irritation of the stomach lining (gastritis).  Determine whether treatment for an H. pylori infection has been successful.How To PrepareBlood antibody test or stool antigen testYou do not need to do anything before you have a blood antibody test or stool antigen test.Stomach biopsy or urea breath testDo not eat or drink for at least 6 hours before a breath test or a stomach biopsy.Many medicines may change the results of this test. Be sure to tell your doctor about all the prescription andnonprescription medicines you take. Your doctor may recommend that you stop taking some of your medicines for up to1 week before having this test.  Do not take antibiotics, proton pump inhibitors (such as Prilosec or Nexium), or medicines containing bismuth (such as Pepto-Bismol) for 1 to 2 weeks before the test.  Do not take H2 blockers, such as Pepcid AC, Zantac, Axid, or Tagamet for 24 hours before the test.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results may mean. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is Done
    • Blood antibody testThe health professional taking a sample of your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Put a gauze pad or cotton ball over the needle site as the needle is removed.  Put pressure on the site and then put on a bandage.Urea breath testThe breath sample is collected when you blow into a balloon or blow bubbles into a bottle of liquid. The healthprofessional taking a sample of your breath will:  Collect a sample of your breath before the test starts.  Give you a capsule or some water to swallow that contains tagged or radioactive material.  Collect samples of your breath at different times. The breath samples will be tested to see whether they contain material formed when H. pylori comes into contact with the radioactive material.  The urea breath test usually takes about 1.5 hours.Stool antigen testThe stool sample for this test may be collected at home. If you are in the hospital, a health professional will help youcollect the sample.To collect the sample, you need to:  Pass stool into a dry container. Either solid or liquid stools can be collected. Be careful not to get urine or toilet tissue in with the stool sample.  Replace the container cap and label the container with your name, your doctors name, and the date the sample was collected.  Wash your hands well after collecting the sample to avoid spreading bacteria.  Deliver the sealed container as soon as possible to your doctors office or directly to the lab.Your doctor may also use a cotton swab inserted into your rectum to collect a stool sample during an exam.Stomach biopsy  Endoscopy is used to collect samples of tissue from the stomach and duodenum. The doctor may collect up to ten tissue samples. For more information, see the medical test Upper Gastrointestinal Endoscopy.  The tissue samples are tested in the lab to see if they contain H. pylori.  In rare cases, a biopsy sample may be placed in a container that promotes the growth of H. pylori bacteria. This is called an H. pylori culture. If bacteria grow in the culture, tests (called susceptibility or sensitivity testing) can determine which antibiotic to use to treat the infection.How It FeelsBlood antibody testThe blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight.You may feel nothing at all from the needle, or you may feel a quick sting or pinch.Urea breath testA urea breath test does not normally cause discomfort.Stool antigen test
    • Collecting a stool sample normally does not cause any discomfort.If your doctor collects the sample during a rectal exam, you may feel some pressure or discomfort as the cotton swab isinserted into your rectum.Stomach biopsyYou may notice a brief, sharp pain when the intravenous (IV) needle is placed in a vein in your arm. The local anestheticsprayed into your throat usually tastes slightly bitter and will make your tongue and throat feel numb and swollen. Somepeople report that they feel as if they cannot breathe at times because of the tube in their throat, but this is a falsesensation caused by the anesthetic. There is always plenty of breathing space around the tube in your mouth andthroat. Remember to relax and take slow, deep breaths.You may experience some gagging, nausea, bloating, or mild abdominal cramping as the tube is moved. Even thoughyou wont be able to talk during the procedure because you have a tube in your throat, you can still communicate. If thediscomfort is severe, alert your doctor with an agreed-upon signal or a tap on the arm.The IV medications will make you feel sleepy. Other side effects—such as heavy eyelids, difficulty speaking, a drymouth, or blurred vision—may last for several hours after the test. The medications may also cause you not toremember much of what happens during the test.RisksBlood antibody testThere is very little chance of a problem from having a blood sample taken from a vein.  You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.  In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.  Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other medicines that thin your blood can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.Urea breath testThere are no known risks or complications with a urea breath test. If radioactive carbon is used, the amount ofradioactivity exposure is extremely small—less than you normally get from being outside during the day.Stool antigen testThere are no risks or complications with a stool sample. However, if you do not wash your hands well after collecting thesample, you may spread germs.Stomach biopsyThere is a slight risk (1 in 10,000) of puncturing the wall of the esophagus, stomach, or duodenum during an endoscopyto collect stomach biopsy samples. The biopsy may also cause some bleeding at the site where the samples arecollected. However, the bleeding usually stops without treatment. For more information, see the medical test UpperGastrointestinal Endoscopy.After the testAfter the test, you may belch and feel bloated for a while. You also may have a tickling, dry throat; slight hoarseness; ora mild sore throat. These symptoms may last several days. Throat lozenges and warm saltwater gargles can helprelieve the throat symptoms. Do not drink alcohol after the test.After the test, contact your doctor immediately if you:  Vomit blood or notice black or bloody stools.  Have trouble swallowing or talking.
    •  Are short of breath or have a fast heartbeat.  Have increasing chest or abdominal pain.  Have neck or shoulder pain.  Have a fever.ResultsHelicobacter pylori tests are used to detect a Helicobacter pylori (H. pylori) infection in the stomach and upper part ofthe small intestine (duodenum).Results from the urea breath test or a stool antigen test are generally available within a few hours. Results from a bloodantibody test are usually available within 24 hours. Results from biopsy samples obtained by endoscopy are usuallyavailable within 48 hours. Results from a biopsy sample that is cultured can take up to 10 days. Blood antibody test Normal: The blood sample does not contain H. pylori antigens. Abnormal: The blood sample contains H. pylori antigens. Urea breath test Normal: The breath sample does not contain the tagged hydrocarbon. Abnormal: The breath sample contains the tagged hydrocarbon. Stool antigen test Normal: The stool sample does not contain H. pylori antigens. This is called a negative test result. However, a negative stool antigen test does not always mean that you do not have an H. pylori infection. Abnormal: The stool sample contains H. pylori antigens. Stomach biopsy Normal: The biopsy sample does not contain H. pylori bacteria. H. pylori bacteria does not grow in a culture of the tissue biopsy samples. See an illustration of a normal stomach as seen during endoscopy . Abnormal: The biopsy sample contains H. pylori bacteria. H. pylori bacteria grows in a culture of the tissue biopsy samples. See an illustration of gastritis caused by H. pylori as seen during endoscopy .What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include the following:  The radioactive urea breath test for H. pylori is not usually done during pregnancy or while you are breast-feeding, because the radiation could harm your child.
    •  Use of antibiotics may affect the results of the urea breath test, the stool antigen test, and stomach biopsy by reducing the number of H. pylori bacteria in the stomach and duodenum.  The use of lansoprazole (Prevacid), rabeprazole (Aciphex), sucralfate (Carafate), omeprazole (Prilosec), famotidine (Pepcid AC), ranitidine (Zantac), nizatidine (Axid), cimetidine (Tagamet), or medicines containing bismuth (such as Pepto-Bismol) can also interfere with the results of the urea breath test and stomach biopsy.  A stomach biopsy may not detect an H. pylori infection that is present if the biopsy samples are taken from areas that are not infected by the H. pylori bacteria.  Rough handling, contamination, or inadequate refrigeration of the blood sample can cause inaccurate blood antibody test results.  When a blood antibody test is done early in an H. pylori infection, the results may be falsely negative because the level of antibodies is too low to measure.  The likelihood of infection with H. pylori increases with age; older adults are more likely to have detectable amounts of the bacteria in their body.What To Think About  The radioactive urea breath test is not recommended for children or for pregnant or breast-feeding women because of exposure to a small amount of radioactivity.  The stool antigen test is the newest and least expensive of the four tests for Helicobacter pylori, but it may not be as accurate as the other tests. The stomach biopsy is very accurate, but it is the most expensive and most risky of the four tests.  A negative stool antigen test does not always mean that an H. pylori infection is not present.  Although many people are infected with H. pylori bacteria, only a few of them will develop peptic ulcer disease. For this reason, other factors (such as a persons symptoms) should be considered when interpreting the results of an H. pylori test.  Blood tests for H. pylori may be positive for several years after the infection; therefore, the urea breath test or a biopsy may be used to determine if treatment has been effective.  If your symptoms persist, an endoscopy may be needed. For more information, see the medical test Upper Gastrointestinal Endoscopy.  Having an infection with H. pylori increases your chances of having cancer of the stomach; but the risk is very low.
    • Helicobacter pyloriIn 1994 the National Institutes of Health Consensus Development Conference concluded thatHelicobacter pylori (H. pylori) infection is the major cause of peptic ulcer disease, present in 90% ofpatients with duodenal ulcer and 80% of gastric ulcers. Worldwide, the prevalence of H. pylori infectionis estimated at 50%. The primary mode of transmission appears to be fecal-oral. In the United Statesthe overall prevalence is 30-40%, with lower prevalence in younger age groups.Immediately following infection, H. pylori causes acute gastritis. Some individuals spontaneously clear H.pylori, but most develop persistent infection, which leads to chronic active gastritis. Subsequentcomplications include gastric and duodenal ulcers, gastric lymphoma, and gastric adenocarcinoma. Anestimated 16% of infected individuals in the U.S. develop duodenal ulcers. Infection in early childhoodincreases risk for later development of gastric adenocarcinoma. Fewer than 5% of infected individualsdevelop gastric lymphoma.H. pylori infection may be diagnosed by invasive (endoscopy) or noninvasive methods. Complicationsincluding GI bleeding, weight loss, older age, or persistence of symptoms after antimicrobial therapy areindications for endoscopy. From endoscopy, the organism may be identified by culture, biopsy, or rapidurease testing (e.g. CLOtest).Noninvasive testing includes serology, fecal antigen testing and urea breath testing.  Enzyme immunoassay (EIA) for IgG antibody to H. pylori is the serologic method of choice for screening patients with uncomplicated dyspepsia. Serum IgG EIA have 90-95% sensitivity and 80-90% specificity. It should be noted that serum IgG assays have markedly reduced sensitivities in HIV-infected patients. Limitations of the test include possible inability to monitor therapy due to a slow decline in antibody levels. A positive result may only indicate exposure to the organism and does not necessarily correlate with active infection. Screening of asymptomatic individuals is not recommended due to the high prevalence of carriers in the general population, especially in the elderly.  Several rapid immunoassays have been developed that produce a qualitative result in 4-10 minutes. Compared with serum EIA, these whole blood rapid immunoassays have reduced sensitivities (80-90%), but comparable specificities.  The noninvasive urea breath test (UBT) has excellent sensitivity and specificity for the diagnosis and assessment of patients post therapy (both exceeding 95%) when compared to invasive methods. However, due to high cost, this testing is not recommended for routine screening in uncomplicated, untreated patients. UBT is useful in follow-up of patients who continue to be symptomatic despite antimicrobial therapy, and may confirm eradication of H. pylori within six weeks after therapy compared with a 6 to 12 month follow-up period with serology for IgG antibody.  The newest FDA-approved noninvasive test is an EIA for detection of H. pylori antigen in stool specimens. Compared to other direct detection tests, the stool antigen test has a sensitivity of 93-98% with specificity of 88-96%. Because the test measures H. pylori antigen it may also be useful in confirming eradication shortly after therapy. Use of antimicrobials, proton pump inhibitors, and bismuth preparations prior to testing may cause false negative results.The antigen test requires a fresh stool specimen submitted in an airtight container and refrigerated priorto transport. Stool in transport media, swabs or a preservative is not appropriate. Specimen requirementfor IgG antibody is one SST tube of blood. Blood collected in a lavender top (EDTA) or light blue top(sodium citrate) tube is also acceptable.Results are reported as negative or positive. The reference value is negative.
    • Sodium (Na) in Blood Test OverviewA sodium test measures the amount of sodium (an electrolyte and a mineral) in the body. Sodium helps regulate thewater balance (the amount of fluid inside and surrounding the cells) and electrolyte balance of the body. Sodium alsoplays an important role in nerve and muscle functions. It carries an electrical charge when it is dissolved in blood.Most of the sodium in the body (about 85%) is found in the fluids that surround the bodys cells (such as blood andlymph fluid). Sodium levels in the body are partially controlled by a hormone called aldosterone, which is produced bythe adrenal glands. Aldosterone causes the kidneys to retain sodium that is normally lost through the urine. (See anillustration of the adrenal glands or the kidneys .) Small amounts of sodium are also lost through the skin insweat.Almost all foods contain sodium naturally or as an ingredient, such as table salt (sodium chloride) or baking soda(sodium bicarbonate) added in processing or while cooking. Many medicines and other products also contain sodium,including laxatives, aspirin, mouthwash, and toothpaste.Too much sodium in the diet may raise blood pressure in some people. For those who already have high bloodpressure, a diet high in sodium may further increase their risk of heart disease, stroke, and kidney damage. Highsodium intake can worsen heart failure and can increase the amount of water retained by the body, leading to swellingof the legs and hands. Taking in more than 4,000 milligrams (mg) of sodium per day causes problems for some people.Low blood sodium levels are uncommon and most often occur as a side effect of taking medications that increaseurination (diuretics). Severe diarrhea or vomiting or heavy sweating may also cause low blood sodium levels.Other electrolytes, such as potassium, calcium, chloride, magnesium, and phosphate, may be measured in a bloodsample at the same time as a blood test for sodium.Why It Is DoneA test to measure sodium levels is done to:  Evaluate the water balance (the amount of fluid inside and surrounding the cells) and electrolyte balance of the body.  Evaluate symptoms that may be caused by abnormal low or high levels of sodium.  Monitor diseases of the kidneys or adrenal glands.How To PrepareNo special preparation is required before having this test.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneBlood testThe health professional drawing blood will  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.
    •  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsA sodium test measures the amount of sodium (an electrolyte and mineral) in the body. Normal values may vary fromlab to lab. SodiumBlood: 135–145 millimoles per liter (mmol/L)Urine: 10–40 mmol/L (can range from undetectable to 150 mmol/L)Many conditions can affect sodium levels.Your health professional will discuss any significant abnormal results with youin relation to your symptoms and medical history.High values  High sodium levels (hypernatremia) can be caused by a high-sodium diet or by not drinking enough water (dehydration).  High sodium levels can also result from abnormally high levels of the hormone aldosterone (hyperaldosteronism) or from dehydration caused by severe vomiting or diarrhea, Cushings syndrome, kidney disease or injury, diabetic ketoacidosis, or a condition caused by the inability to regulate levels of water in the body properly (diabetes insipidus).Low values  Low sodium levels (hyponatremia) can be caused by excessive sweating, burns, severe vomiting or diarrhea, drinking too much water (psychogenic polydipsia), or poor nutrition.  Low sodium levels can also be caused by underactive adrenal glands or thyroid gland, heart failure, kidney disease, cirrhosis, cystic fibrosis, or SIADH (syndrome of inappropriate antidiuretic hormone secretion).What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Medications, such as birth control pills, corticosteroids, antibiotics, estrogens, tricyclic antidepressants, heparin, nonsteroidal anti-inflammatory drugs (NSAIDs), diuretics, lithium, and many medications used to treat high blood pressure.
    •  High levels of glucose, triglycerides, or protein.  The amount of sodium in intravenous fluids given during surgery or a hospitalization.What To Think About  A rapidly changing sodium level often causes more symptoms than when the level changes slowly. Symptoms of an abnormal sodium level include confusion, lack of energy (lethargy), or seizures.  It is important to evaluate the bodys water content (too much or too little water) when evaluating a low sodium level.  To determine whether the body is releasing too little or too much sodium in the urine, a value called the fractional excretion of sodium (FENA) is calculated from the amounts of sodium and creatinine in blood and urine. In a person with kidney failure, a low FENA may indicate that reduced blood flow to the kidneys is causing the kidney failure. A urine test for sodium may be done. For more information, see the medical test Sodium in Urine.  Other electrolytes, such as calcium, chloride, magnesium, potassium, phosphate, blood urea nitrogen (BUN), and creatinine, may be measured in a blood sample at the same time as a blood test for sodium. For more information, see the medical tests Calcium in Blood, Chloride (Cl), Magnesium (Mg), Potassium in Blood, Phosphate, Blood Urea Nitrogen, and Creatinine and Creatinine Clearance.
    • Sodium (Na) in Urine Test OverviewA test for sodium in the urine is a 24-hour test or a one-time (spot) test that measures the amount of sodium (anelectrolyte and mineral) in the urine. Sodium helps regulate the water balance (the amount of fluid inside andsurrounding the cells) and electrolyte balance of the body. Sodium also plays an important role in nerve and musclefunctions.Most of the sodium in the body (about 85%) is found in the fluids that surround the bodys cells (such as blood andlymph fluid). Sodium levels in the body are partially controlled by a hormone called aldosterone, which is produced bythe adrenal glands. Aldosterone causes the kidneys to retain sodium that is normally lost through the urine. (See anillustration of the adrenal glands or the kidneys .) Small amounts of sodium are also lost through the skin insweat.Almost all foods contain sodium naturally or as an ingredient, such as table salt (sodium chloride) or baking soda(sodium bicarbonate) added in processing or while cooking. Many medicines and other products also contain sodium,including laxatives, aspirin, mouthwash, and toothpaste.Too much sodium in the diet may raise blood pressure in some people. For those who already have high bloodpressure, a diet high in sodium may further increase their risk of heart disease, stroke, and kidney damage. Highsodium intake can worsen heart failure and can increase the amount of water retained by the body, leading to swellingof the legs and hands. Taking in more than 4,000 milligrams (mg) of sodium per day causes problems for some people.Low sodium levels are uncommon and most often occur as a side effect of taking medications that increase urination(diuretics). Severe diarrhea or vomiting or heavy sweating may also cause low sodium levels.Why It Is DoneA test to measure sodium levels is done to:  Evaluate the water balance (the amount of fluid inside and surrounding the cells) and electrolyte balance of the body.  Evaluate symptoms that may be caused by abnormal low or high levels of sodium.  Monitor diseases of the kidneys or adrenal glands.How To PrepareNo special preparation is required before having this test.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneUrine sodium can be measured in a single urine sample but is usually measured in a sample taken from all the urineproduced in a 24-hour period.Clean-catch midstream one-time urine collectionThis collection method prevents contamination of the sample.  Wash your hands to make sure they are clean before collecting the urine.  If the collection container has a lid, remove it carefully and set it down with the inner surface up. Avoid touching the inside of the container with your fingers.  Clean the area around your genitals.
    • o A man should retract the foreskin, if present, and clean the head of his penis thoroughly with medicated towelettes or swabs. o A woman should spread open the folds of skin around her vagina with one hand, then use her other hand to clean the area around her vagina and urethra thoroughly with medicated towelettes or swabs. She should wipe the area from front to back to avoid contaminating the urethra with bacteria from the anus.  Begin urinating into the toilet or urinal. A woman should continue to hold apart the folds of skin around the vagina while she urinates.  After the urine has flowed for several seconds, place the collection container into the stream and collect about 2 fl oz(59 mL) of this ―midstream‖ urine without interrupting the flow.  Avoid touching the rim of the container to your genital area, and avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.  Finish urinating into the toilet or urinal.  Carefully replace the lid on the container and return it to the lab. If you are collecting the urine at home and cannot get it to the lab within an hour, refrigerate it.Urine collection over 24 hours  The collection period usually starts in the morning. When you first get up, empty your bladder but do not save this urine. Write down the time that you urinated to mark the beginning of your 24-hour collection period.  For the next 24 hours, collect all your urine. Your health professional or lab will usually provide you with a large container that holds about 1 gal(3.8 L) and has a small amount of preservative in it. Urinate into a smaller, clean container and then pour the urine into the large container. Avoid touching the inside of the container with your fingers.  Keep the large container in the refrigerator during the collection period.  Empty your bladder for the final collection at or just before the end of the 24-hour period. Add this final sample to the large container and record the time.  Avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.How It FeelsThere is normally no discomfort involved with collecting a one-time or 24-hour urine sample.RisksThere are no risks associated with collecting a one-time or 24-hour urine sample.ResultsA test for sodium in the urine is a 24-hour test or a one-time (spot) test that measures the amount of sodium (anelectrolyte and a mineral) in the urine.NormalNormal results may vary from lab to lab. Sodium in 24-hour urine collectionAverage amount of sodium in 40 to 220 milliequivalents (mEq)/day or 40 to 220 millimoles (mmol) (SI units) in a 24-diet: hour sample Sodium in one-time urine sampleAverage amount of sodium in diet: Greater than 20 milliequivalents per liter (mEq/L)Many conditions can affect sodium levels.Your health professional will discuss any significant abnormal results with youin relation to your symptoms and medical history.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:
    •  Medications, such as birth control pills, corticosteroids, antibiotics, estrogens, tricyclic antidepressants, heparin, nonsteroidal anti-inflammatory drugs (NSAIDs), diuretics, lithium, and many medications used to treat high blood pressure.  High levels of glucose, triglycerides, or protein.  The amount of sodium in intravenous fluids given during surgery or a hospitalization.What To Think About  Sodium levels can also be measured in a blood test. For more information, see the medical test Sodium in Blood.  Health professionals compare urine sodium values to blood sodium values to help determine which conditions or medications may be causing fluid or electrolyte imbalances. Urine sodium values are frequently inversely related to blood sodium values, meaning that the values may be low in one while high in the other and vice versa. Urine sodium values are affected by medications and hormones.  To determine whether the body is releasing too little or too much sodium in the urine, a value called the fractional excretion of sodium (FENA) is calculated from the amounts of sodium and creatinine in blood and urine. In a person with kidney failure, a low FENA may indicate that reduced blood flow to the kidneys is causing the kidney failure.
    • Calcium (Ca) in Blood Test OverviewA test for calcium in the blood measures the calcium level in the body that is not stored in the bones. Calcium is themost plentiful mineral in the body and one of the most important. The body needs it to build and repair bones and teeth,help nerves function, make muscles contract, clot blood, and allow proper function of the heart. Almost all of the calciumin the body is stored in bone. The rest is found in the blood.Under normal conditions, the level of calcium in the blood is carefully controlled. When blood calcium levels fall(hypocalcemia), calcium is released from bones to restore proper blood levels. When blood calcium levels rise(hypercalcemia), the excess calcium may be stored in bone or passed out of the body in urine and stool. This controldepends upon the:  Amount of calcium in the diet.  Amount of calcium and vitamin D absorbed by the intestines.  Amount of phosphate in the body.  Production of certain hormones, including parathyroid hormone, calcitonin, and estrogen.Vitamin D and certain hormones (such as parathyroid hormone and calcitonin) help control the total amount of calciumin the body. They also regulate the amount of calcium absorbed from food and the amount removed from the body bythe kidneys. The blood levels of phosphate are closely linked to calcium levels. They usually work in opposite directions:As blood calcium levels rise, phosphate levels fall.Getting enough calcium [at least 1000 mg(1 g) a day] in the diet is important, since the body loses calcium every day.The main sources of calcium are dairy products (milk, cheese), eggs, fish, green vegetables, and fruit. Most people whohave abnormal blood calcium levels do not have any symptoms. Usually, calcium levels need to be extremely high orlow to cause symptoms.Why It Is DoneA blood calcium test may be done:  To evaluate suspected problems with the parathyroid glands or kidneys, certain types of cancers and bone diseases, inflammation of the pancreas (pancreatitis), kidney stones, and some abnormal results noted on an electrocardiogram (EKG) test.  To investigate symptoms that may be caused by a very low calcium level in the blood. These symptoms may include muscle cramping and twitching, tingling in the fingers and around the mouth, spasms, confusion, or depression.  To investigate symptoms that may be caused by a very high calcium level in the blood. These symptoms may include weakness, lack of energy, poor appetite, nausea and vomiting, constipation, frequent urination, or abdominal or bone pain.  As part of a routine blood screening test.A blood calcium test cannot be used to detect poor calcium intake or the loss of calcium from the bones (osteoporosis).Blood calcium levels are usually kept within normal limits even when a persons diet does not contain enough calcium.Calcium is removed from the bones to keep blood levels normal because calcium is important to brain, muscle, heart,and nerve function. Other tests, such as bone densitometry, measure the amount of calcium in the bones.How To PrepareDo not take calcium supplements for 8 to 12 hours before having a blood calcium test. Your health professional willinstruct you if you should not eat or drink anything before your test.How It Is DoneThe health professional drawing blood will:
    •  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsA test for calcium in the blood measures the calcium level in the body that is not stored in the bones.NormalNormal values may vary from lab to lab. Calcium in bloodAdults: 9.0–10.5 milligrams per deciliter (mg/dL)Normal blood calcium values are higher in children because of their rapid growth and active bone formation. Calciumlevels in children can rise to 12 mg/dL during periods of rapid bone growth.An ionized calcium test measures the amount of calcium that is not bound to protein in the blood. The level of ionizedcalcium in the blood is not affected by the amount of protein in the blood. Ionized calciumAdults: 4.65–5.28 milligrams per deciliter (mg/dL)High values  High levels of calcium in the blood may be caused by prolonged immobilization (such as bed rest), hyperparathyroidism, kidney disease, tuberculosis, or cancer that has spread to the bones. Certain cancers may produce a substance that raises blood calcium levels.  High levels of calcium in the blood can be caused by eating a diet with excessive amounts of vitamin D, vitamin A, or calcium. Eating large amounts of milk products or taking too many calcium-containing medications (such as antacids or vitamin supplements) can cause high blood calcium levels.
    •  High levels of calcium in the blood can be caused by dehydration, sarcoidosis, chronic liver or kidney problems, Pagets disease, and Addisons.  In rare cases, hyperthyroidism may increase blood calcium levels.Low values  Low levels of calcium in the blood can be caused by an underactive parathyroid gland (hypoparathyroidism), problems that prevent the intestines from absorbing calcium and other nutrients from food (malabsorption syndrome), bone problems, kidney disease, acute pancreatitis, or decreased amounts of the protein albumin in the blood (hypoalbuminemia).  Decreased ionized calcium levels may be caused by decreased magnesium levels.  Pregnant women and older men may also have low calcium levels.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Drinking excessive amounts of milk, antacids, calcium salts, and calcium supplements.  Medications, such as diuretics, acetazolamide (Diamox), albuterol, estrogen, birth control pills, corticosteroids, and some medications that control seizures.  Long-term or excessive use of vitamin D or lithium, overuse of laxatives, or an overdose of theophylline or aspirin.  Having many blood transfusions in a short period of time.What To Think About  More than one blood test may be needed to determine whether blood calcium levels are abnormally high.  Low blood levels of calcium may be caused by low levels of protein (albumin) in the blood, because about half of all calcium in the blood is bound to albumin. For this reason, an ionized calcium level (which is not bound to albumin) and a blood albumin level may also be measured. For more information, see the medical test Total Serum Protein.  Other tests that may be done to determine the cause of abnormal blood calcium levels include blood tests for parathyroid hormone (PTH), chloride, acid phosphatase, alkaline phosphatase, and vitamin D. For more information, see the medical tests Parathyroid Hormone and Alkaline Phosphatase.  In a person with cancer, a high blood calcium level is considered an emergency. Treatment must be started immediately to prevent the person from becoming increasingly confused and dehydrated.  Since calcium affects heart functioning, a high or low blood calcium level may be suspected if abnormal results are noted on an electrocardiogram (EKG) test. A blood calcium test will be done to help determine the cause of the abnormal EKG results.  Calcium levels can also be measured in the urine. For more information, see the medical test Calcium in Urine.
    • Potassium (K) in Blood Test OverviewA potassium test measures the amount of potassium (an electrolyte and mineral) in the blood. Potassium is needed forproper nerve and muscle (including heart) function. It helps regulate the water balance (the amount of fluid inside andsurrounding the cells) and electrolyte balance of the body.Potassium levels in the blood usually vary with sodium levels. When sodium levels increase, potassium levels decrease,and vice versa. Potassium levels also are affected by a hormone called aldosterone, which is produced by the adrenalglands.Potassium levels can be affected by kidney function, blood pH, the amount of potassium in the diet, hormone levelsin the body, excessive vomiting, and taking certain medications (including potassium supplements). Certain cancertherapies that rapidly destroy cancer cells can increase blood levels of potassium.Many foods are rich in potassium, including scallops, potatoes, figs, bananas, prune juice, orange juice, and squash. Abalanced diet generally contains enough potassium for the bodys needs. However, potassium is released into the urineby the kidneys, even when the blood potassium level is low. Therefore, blood potassium deficiency can develop quicklyif the body is unable to control potassium levels because of a disease or medication.A potassium level that is too high or too low can be dangerous. Abnormal potassium levels may cause symptoms suchas muscle cramps or weakness, nausea, diarrhea, frequent urination, dehydration, low blood pressure, confusion,irritability, paralysis, and changes in heart rhythm.Other electrolytes, such as sodium, calcium, chloride, magnesium, and phosphate, may be measured in a blood sampleat the same time as a blood test for potassium.Why It Is DoneA test to measure potassium is done to:  Detect potassium levels in the blood that are too low (hypokalemia) or too high (hyperkalemia). This may be done for people being treated with medications (such as diuretics) that affect potassium levels and for people receiving kidney dialysis.  Monitor the success of therapy to correct an abnormal high or low blood potassium level.  Evaluate people with high blood pressure who may have a problem with their kidneys or adrenal glands.  Monitor the effects of total parenteral nutrition (TPN) on blood potassium levels.  Monitor certain cancer therapies that may cause cell lysis syndrome, a condition that occurs when cancer cells are rapidly destroyed. Cell lysis syndrome causes abnormally high blood levels of certain electrolytes, including potassium.How To PrepareNo special preparation is required before having this test.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.
    •  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsA potassium test measures the level of potassium (an electrolyte and mineral) in the blood. Normal values may varyfrom lab to lab. Blood potassium levels also vary with age. Potassium (K) Adults: 3.5–5.0 milliequivalents per liter (mEq/L) or millimoles per liter (mmol/L) Children: 3.4–4.7 mEq/L or mmol/L Infants: 4.1–5.3 mEq/L or mmol/L Newborns: 3.9–5.9 mEq/L or mmol/LMany conditions can affect potassium levels.Your health professional will discuss any significant abnormal results withyou in relation to your symptoms and medical history.High values  High blood potassium levels may be caused by damage or injury to the kidneys that prevents them from removing potassium from the blood normally.  High blood potassium levels can also be caused by conditions that release potassium from the bodys cells into the blood. These conditions include severe burns, crushing injuries, heart attack, and diabetic ketoacidosis.  Excessive use of potassium supplements can also cause high levels of potassium in the blood.  Excess acid in the blood increases potassium levels by causing the potassium within the bodys cells to ―leak‖ out of cells and into the blood.  Some medications, such as angiotensin-converting enzyme (ACE) inhibitors, can cause high potassium levels.Low values  Low blood potassium levels can be caused by excessive production in the adrenal glands of the hormone aldosterone (hyperaldosteronism), by Cushings syndrome, or by significant water loss from the body.
    •  Medications, such as diuretics, are a common cause of low potassium levels.  Low blood potassium levels can also be caused by a poor diet (malnutrition) or by conditions that result in rapid potassium loss (such as vomiting, diarrhea, or excessive sweating).  Other conditions that can cause low blood potassium levels include severe burns, cystic fibrosis, alcoholism, and certain kidney diseases, such as Bartters syndrome. Bartters syndrome is a condition characterized by enlargement of certain kidney cells. It is more common in children and may be associated with an abnormally short stature (dwarfism). The cause of Bartters syndrome is not fully known.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Potassium supplements.  Medications, such as antibiotics that contain potassium (such as a type of penicillin g), nonsteroidal anti-inflammatory drugs (NSAIDs), heparin, insulin, glucose, corticosteroids, diuretics, medications used to treat high blood pressure and heart disease, and natural licorice (Glycyrrhiza glabra).  The overuse of laxatives.  Collecting a blood sample immediately after using an elastic band on the arm or while clenching the fist. These actions can damage red blood cells, causing the damaged cells to release potassium into the blood. Therefore, a high blood potassium value should be confirmed through another blood test.What To Think About  Low blood potassium values are more common than high blood potassium values.  An electrocardiograph test (EKG) may show evidence of a very high or very low blood potassium level because of the effect potassium has on the heart. For more information, see the medical test Electrocardiogram.  If blood potassium levels are low, the level of potassium in the urine may be measured to determine whether large amounts of potassium are being released by the kidneys. For more information, see the medical test Potassium in Urine.  Other electrolyte tests, such as sodium, calcium, chloride, magnesium, phosphate, blood urea nitrogen (BUN), and creatinine, are often done at the same time as a test for potassium. For more information, see the medical tests Sodium in Blood, Calcium in Blood, Chloride (Cl), Magnesium (Mg), Phosphate, Blood Urea Nitrogen, and Creatinine and Creatinine Clearance.
    • Potassium (K) in Urine Test OverviewA test for potassium in the urine is a 24-hour test or a one-time (spot) test that measures the amount of potassium (anelectrolyte and mineral) in the urine. Potassium is needed for proper nerve and muscle (including heart) function. Ithelps regulate the water balance (the amount of fluid inside and surrounding the cells) and electrolyte balance of thebody.Potassium levels usually vary with sodium levels. When sodium levels increase, potassium levels decrease, and viceversa. Potassium levels are also affected by a hormone called aldosterone, which is produced by the adrenal glands.Potassium levels can be affected by kidney function, blood pH, the amount of potassium in the diet, hormone levelsin the body, excessive vomiting, and taking certain medications (including potassium supplements). Certain cancertherapies that rapidly destroy cancer cells can also increase levels of potassium.Many foods are rich in potassium, including scallops, potatoes, figs, bananas, prune juice, orange juice, and squash. Abalanced diet generally contains enough potassium for the bodys needs. However, potassium is released into the urineby the kidneys, even if the blood potassium level is low. Therefore, blood potassium deficiency can develop quickly ifthe body is unable to control potassium levels because of a disease or medication.Why It Is DoneA test to measure potassium is done to:  Detect potassium levels in the urine that are too low or too high. This may be done for people being treated with medications (such as diuretics) that affect potassium levels and for people receiving kidney dialysis.  Evaluate kidney function and fluid balance.  Monitor the success of therapy to correct an abnormal potassium level.  Evaluate people with high blood pressure who may have a problem with their kidneys or adrenal glands.  Monitor the effects of total parenteral nutrition (TPN) on potassium levels.  Monitor certain cancer therapies that may cause cell lysis syndrome, a condition that occurs when cancer cells are rapidly destroyed. Cell lysis syndrome causes abnormally high levels of certain electrolytes, including potassium.How To PrepareNo special preparation is required before having this test.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneUrine potassium can be measured in a single urine sample but is usually measured in a sample taken from all the urineproduced in a 24-hour period.Clean-catch midstream one-time urine collectionThis collection method prevents contamination of the sample.  Wash your hands to make sure they are clean before collecting the urine.  If the collection container has a lid, remove it carefully and set it down with the inner surface up. Avoid touching the inside of the container with your fingers.  Clean the area around your genitals.
    • o A man should retract the foreskin, if present, and clean the head of his penis thoroughly with medicated towelettes or swabs. o A woman should spread open the folds of skin around her vagina with one hand, then use her other hand to clean the area around her vagina and urethra thoroughly with medicated towelettes or swabs. She should wipe the area from front to back to avoid contaminating the urethra with bacteria from the anus.  Begin urinating into the toilet or urinal. A woman should continue to hold apart the folds of skin around the vagina while she urinates.  After the urine has flowed for several seconds, place the collection container into the stream and collect about 2 fl oz(59 mL) of this ―midstream‖ urine without interrupting the flow.  Avoid touching the rim of the container to your genital area, and avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.  Finish urinating into the toilet or urinal.  Carefully replace the lid on the container and return it to the lab. If you are collecting the urine at home and cannot get it to the lab within an hour, refrigerate it.Urine collection over 24 hours  The collection period usually starts in the morning. When you first get up, empty your bladder but do not save this urine. Write down the time that you urinated to mark the beginning of your 24-hour collection period.  For the next 24 hours, collect all your urine. Your health professional or lab will usually provide you with a large container that holds about 1 gal(3.8 L) and has a small amount of preservative in it. Urinate into a smaller, clean container and then pour the urine into the large container. Avoid touching the inside of the container with your fingers.  Keep the large container in the refrigerator during the collection period.  Empty your bladder for the final collection at or just before the end of the 24-hour period. Add this final sample to the large container and record the time.  Avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.How It FeelsThere is normally no discomfort involved with collecting a one-time or 24-hour urine sample.RisksThere are no risks associated with collecting a one-time or 24-hour urine sample.ResultsA test for potassium in the urine is a 24-hour test or a one-time (spot) test that measures the amount of potassium (anelectrolyte and mineral) in the urine.NormalNormal results may vary from lab to lab. Potassium in urineAverage amount of potassium in diet: 25 to 125 millimoles per liter (mmol/L)/24-hour sampleMany conditions can affect potassium levels.Your health professional will discuss any significant abnormal results withyou in relation to your symptoms and medical history.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Potassium supplements.  Medications, such as antibiotics that contain potassium (such as a type of penicillin G), nonsteroidal anti-inflammatory drugs (NSAIDs), heparin, insulin, glucose, corticosteroids, diuretics, medications used to treat high blood pressure and heart disease, and natural licorice (Glycyrrhiza glabra).
    •  The overuse of laxatives.  Excessive vomiting.  Failing to collect exactly 24 hours of urine.What To Think About  Potassium levels can also be measured in a blood test. For more information, see the medical test Potassium in Blood.  Health professionals compare urine potassium values to blood potassium values to help determine which conditions or medications may be causing fluid or electrolyte imbalances. Urine potassium values are frequently inversely related to blood potassium values, meaning that the values may be low in one while high in the other and vice versa. Urine potassium values are affected by medications and hormones.
    • Phosphate in Blood Test OverviewA phosphate test measures the amount of the mineral phosphate in a blood sample. The body needs phosphate to buildand repair bones and teeth, help nerves function, and make muscles contract. Most of the bodys phosphate (about85%) is found in bones. The rest of it is stored in tissues throughout the body.The kidneys help control the amount of phosphate in the blood. Extra phosphate is filtered by the kidneys andpasses out of the body in the urine. A high level of phosphate in the blood is usually caused by a kidney problem.The amount of phosphate in the blood affects the level of calcium in the blood. Calcium and phosphate usually arepresent in opposite amounts: As blood calcium levels rise, phosphate levels fall. For this reason, phosphate and calciumlevels are usually measured at the same time.Why It Is DoneA test to measure phosphate in blood may be done to:  Check phosphate levels if you have kidney disease or bone disease.  Help find problems with certain glands, such as the parathyroid glands.  Check phosphate levels if you have diabetic ketoacidosis.How To PrepareMany medicines can change the results of this test. Be sure to tell your doctor about all the nonprescription andprescription medicines you take.Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or whatthe results will indicate. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).How It Is DoneBlood testThe health professional taking a sample of your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Put a gauze pad or cotton ball over the needle site as the needle is removed.  Put pressure on the site and then put on a bandage.Heel stickIn a newborn baby, the blood sample is usually taken from the heel (heel stick).For a heel stick blood sample, several drops of blood are collected from the heel of your baby. The skin of the heel isfirst cleaned with alcohol and then punctured with a small sterile lancet. Several drops of blood are collected in a smalltube. When enough blood has been collected, a gauze pad or cotton ball is placed over the puncture site. Pressure ismaintained on the puncture site briefly, and then a small bandage is usually applied.How It Feels
    • Blood testYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing your blood, the condition of your veins, and your sensitivity to pain.Heel stickA brief pain, like a sting or a pinch, is usually felt when the lancet punctures the skin. Your baby may feel a littlediscomfort with the skin puncture.RisksBlood testThere is very little risk of complications from having blood drawn from a vein. You may develop a small bruise at thepuncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle iswithdrawn.In rare cases, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and isusually treated by applying a warm compress several times daily.Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell the health professional before your blood is drawn.Heel stickThere is very little risk of a serious problem developing from a heel stick. A small bruise may develop at the puncturesite.Continued bleeding can be a problem for babies with bleeding disorders. There is a possibility that a bleeding problemmay be discovered while collecting the blood for this test.ResultsA phosphate test measures the amount of the mineral phosphate in a blood sample. Phosphate levels are usuallyhigher in children than in adults because of the active bone growth that occurs in children.Results are usually available within 1 to 2 hours.NormalNormal values may vary from lab to lab. Phosphate in blood Adults: 2.3–4.5 milligrams per deciliter (mg/dL) Children: 4–6 mg/dL Babies: 4.5–9 mg/dL Premature babies: 5.4–10.9 mg/dLHigh valuesHigh phosphate levels may be caused by:
    •  Kidney disease, underactive parathyroid glands (hypoparathyroidism), acromegaly, rhabdomyolysis, healing fractures, untreated diabetic ketoacidosis, or certain bone diseases.  Too much vitamin D in the body.  A decrease in magnesium levels.  Pregnancy.Low valuesLow phosphate levels may be caused by:  Hyperparathyroidism, certain bone diseases (such as osteomalacia), lack of vitamin D, severe burns, or some kidney or liver diseases.  Severe malnutrition or starvation.  A condition such as sprue that prevents the intestines from absorbing nutrients properly.  Alcohol dependence.  High calcium levels.What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  Drinking alcohol before the test.  Using some medicines that can increase phosphate levels, such as androgen hormones, anabolic steroids, and enemas that contain phosphate.  Taking too much vitamin D.  Using some medicines that can decrease phosphate levels, such as antacids, insulin, acetazolamide, and epinephrine. A large infusion of sugar (glucose) that causes insulin levels to increase can also decrease phosphate levels.  Having a disease, such as lymphoma, that causes calcium levels to rise or fall.  Having a rare disease, such as diabetes insipidus, that causes the kidneys to produce large amounts of urine.What To Think About  Results of a test to measure phosphate in blood are not useful alone. Other electrolytes (such as chloride, magnesium, potassium, and sodium) may also be measured. For more information, see the medical tests Chloride, Magnesium, Potassium, and Sodium.  Other blood tests, such as a blood urea nitrogen (BUN) test or a creatinine test, can also be used to check kidney function. For more information, see the medical tests Blood Urea Nitrogen and Creatinine and Creatinine Clearance.  Children with low phosphate levels may grow more slowly than other children.  Low phosphate levels may occur in people who have type 2 diabetes or when a person who has diabetic ketoacidosis is being treated with insulin.
    • Magnesium (Mg) Test OverviewA magnesium test measures the level of magnesium in the blood. Magnesium is an important electrolyte needed forproper muscle, nerve, and enzyme function. It also helps regulate energy production in cells and is needed to moveother electrolytes (potassium and sodium) into and out of cells.Magnesium is one of the most abundant minerals in the body and is found mainly inside the bones and cells. Only a tinyamount of magnesium is normally present in the blood. It is absorbed through the small intestine during fooddigestion. A balanced diet contains enough magnesium for the bodys needs.Magnesium deficiency is rare, but when it occurs it is often caused by conditions that interfere with the ability of theintestines to absorb magnesium from food, by poor diet, or by losing magnesium from prolonged vomiting or diarrhea.People who have diabetes and those who drink excessive amounts of alcohol, overuse diuretics, or have burns over alarge area of their bodies are at high risk for developing a magnesium deficiency. Symptoms of a magnesium deficiencyinclude weakness, dizziness, irregular heartbeat, tremors, and seizures.An increased amount of magnesium in the blood can be caused by kidney failure or by excessive use of certainmedications that contain magnesium (such as antacids or laxatives). Occasionally, an increased blood level ofmagnesium can be caused by problems with the thyroid or parathyroid glands (such as hypothyroidism orhyperparathyroidism).Too much magnesium in the blood can cause low blood pressure, nausea, vomiting, diarrhea, dizziness, muscleweakness, and slurred speech. Very high levels of magnesium in the blood can lead to heart problems or an inability tobreathe, especially in people with kidney disease.Tests for other electrolytes, such as calcium, potassium, sodium, and phosphorus, may be done along with a test formagnesium.Why It Is DoneA test for magnesium is done to:  Determine a cause for nerve and muscle problems, such as muscle twitches, irritability, and muscle weakness.  Determine the cause of a low calcium or potassium level that is not improving despite treatment.  Screen for an excess of magnesium or for a magnesium deficiency (especially in people taking diuretics).  Determine whether people with heart problems need additional magnesium. Low magnesium levels can increase the risk of potentially life-threatening heart rhythm problems.  Measure levels when magnesium is being given for medical treatment.How To PrepareDo not take medications containing magnesium for at least 3 days before this test. This includes antacids that containmagnesium, certain laxatives (such as milk of magnesia or Epsom salts), magnesium supplements, and certaindiuretics.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.
    •  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain felt depends on the skill ofthe health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsA magnesium test measures the level of magnesium in the blood. Normal values may vary from lab to lab. Magnesium 1.3–2.4 milligrams per deciliter (mg/dL)High valuesHigh magnesium levels in the blood may be caused by kidney failure, dehydration, hypothyroidism,hyperparathyroidism, or Addisons disease.Low values  Low magnesium levels in the blood may indicate alcoholism, a diet low in magnesium, pancreatitis, long- term diarrhea, or a condition (such as sprue) that prevents the intestines from absorbing the nutrients from food.  Low magnesium levels in the blood may also be caused by severe burns, high blood calcium levels (hypercalcemia), diabetic ketoacidosis, hyperthyroidism, malnutrition, long-term (chronic) kidney disease, or underactive parathyroid glands (hypoparathyroidism).  Magnesium blood levels may normally be low in the second and third trimesters of pregnancy.  Low magnesium levels may be present in toxemia of pregnancy (preeclampsia).What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Excessive use of medications that contain magnesium. This includes antacids that contain magnesium, certain laxatives (such as milk of magnesia or Epsom salts), and magnesium supplements.  Medications. Some antibiotics, insulin, and long-term use of diuretics can lower magnesium levels.  Recent intravenous (IV) fluids, such as fluids given during surgery.What To Think About
    •  A test for magnesium may be done along with testing for other electrolytes, such as calcium, chloride, potassium, and phosphorus. For more information, see the medical tests Calcium (Ca) in Blood, Chloride (Cl), Potassium (K) in Blood, and Phosphate in Blood.  The amounts of magnesium and calcium in the body are often closely related. Phosphate in Urine Test OverviewThe phosphate urine test measures the amount of the mineral phosphate in a urine sample that is collected over 24hours (24-hour urine test). The body needs phosphate to build and repair bones and teeth, help nerves function, andmake muscles contract. Most of the bodys phosphate (about 85%) is found in bones. The rest of it is stored in tissuesthroughout the body.The kidneys help control the amount of phosphate in the body. Extra phosphate is filtered by the kidneys andpasses out of the body in the urine; if there is not enough phosphate, less is found in the urine. A high level ofphosphate in the body is usually caused by a kidney problem.Why It Is DoneA test to measure phosphate in urine may be done to:  Help diagnose kidney problems that affect phosphate levels.  Help find the cause of kidney stones.How To PrepareCalcium and phosphate levels are often measured at the same time. If your calcium is also being measured, you mayneed to follow a special diet that is either high or low in calcium for several days before the test.Many medicines can change the results of this test. Be sure to tell your doctor about all the nonprescription andprescription medicines you take.Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or whatthe results may indicate. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).How It Is DoneUrine phosphate is usually measured in a sample taken from all the urine produced in a 24-hour period.To collect your urine for 24 hours:  You start collecting your urine in the morning. When you first get up, empty your bladder but do not save this urine. Write down the time that you urinated to mark the beginning of your 24-hour collection period.  For the next 24 hours, collect all your urine. Your doctors office or lab will usually provide you with a large container that holds about 1 gal(4 L). The container has a small amount of preservative in it. Urinate into a small, clean container and then pour the urine into the large container. Do not touch the inside of the container with your fingers.  Keep the large container in the refrigerator for the 24 hours.  Empty your bladder for the final time at or just before the end of the 24-hour period. Add this urine to the large container and record the time.  Do not get toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.How It FeelsThere is no pain while collecting a 24-hour urine sample.Risks
    • There is no chance for problems while collecting a 24-hour urine sample.ResultsThe phosphate urine test measures the amount of the mineral phosphate in a urine sample that is collected over 24hours (24-hour urine test).NormalNormal values may vary from lab to lab. Results are usually available in 1 to 2 days. Phosphate in urine Adults: 0.9–1.3 grams (g) per 24-hour urine 13–42 millimoles (mmol) per sample day Calcium- and phosphate-restricted Less than 1.0 g per 24-hour urine Less than 32 mmol per day diet: sampleMany conditions can change phosphate levels. Your doctor will talk with you about any abnormal results that may berelated to your symptoms and medical history.High valuesHigh phosphate levels may be caused by:  Kidney diseases.  An overactive parathyroid gland (hyperparathyroidism).  Not getting enough vitamin D.  Taking too much vitamin D.  Some bone diseases (such as osteomalacia).Low valuesLow urine phosphate levels may be caused by:  An underactive parathyroid gland (hypoparathyroidism).  Kidney or liver diseases.What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  Taking certain medicines, such as diltiazem (such as Cardizem), aspirin, corticosteroids, diuretics, or parathyroid hormone.  Taking a lot of antacids.  Not collecting all of your urine within the 24-hour collection period.What To Think About  Phosphate may also be measured in the blood. For more information, see the medical test Phosphate in Blood.  Results of a test to measure phosphate in urine are seldom useful on their own. They should always be interpreted along with the results of other tests.  The loss of too much phosphate into the urine may cause conditions that damage the bones, such as rickets or osteomalacia.
    • Chloride (Cl) Test OverviewA chloride test measures the level of chloride in your body. Chloride is one of the most important electrolytes in theblood, along with sodium, potassium, and calcium. Chloride helps keep the amount of fluid inside and outside of yourcells in balance. It also helps maintain proper blood volume, blood pressure, and pH of your body fluids. Tests forsodium, potassium, and bicarbonate are usually done at the same time as a blood test for chloride.Most of the chloride in your body comes from table salt (sodium chloride) in the diet. Chloride is absorbed by theintestines during food digestion. Any excess chloride is passed out of your body through the urine. Chloride levels inyour blood generally rise and fall along with sodium levels in your blood.The amount of chloride is indirectly regulated by the hormone aldosterone, which also regulates the amount of sodiumin your blood. When the amount of sodium in your blood decreases, the amount of chloride decreases as well, and viceversa. The level of chloride in your blood is also related to the level of bicarbonate. When the amount of bicarbonatedecreases, the amount of chloride normally increases, and vice versa.Occasionally a test for chloride can be done on a sample of all your urine collected over a 24-hour period (called a 24-hour urine sample) to evaluate how much chloride is being released into your urine.Chloride can also be measured in skin sweat to test for cystic fibrosis.Why It Is DoneA test for chloride may be done to:  Evaluate the electrolyte balance in your body. Too little chloride can cause muscle twitching, muscle spasms, or shallow breathing. Too much chloride can be associated with rapid deep breathing, weakness, confusion, and coma.  Determine whether a problem with your kidneys or adrenal glands is present.  Determine the cause for high blood pH. A condition called metabolic alkalosis can be caused by a loss of acid from your body (for example, from a loss of electrolytes through prolonged vomiting or diarrhea). Metabolic alkalosis can also result when your body loses too much sodium or from eating excessive amounts of baking soda (sodium bicarbonate).How To PrepareNo special preparation is needed before having this test.How It Is DoneCollection of the blood sampleThe health professional drawing your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.24-hour urine sample collection
    •  The collection period usually starts in the morning. When you first get up, empty your bladder but do not save this urine. Write down the time that you urinated to mark the beginning of your 24-hour collection period. Drink extra fluids during the 24-hour collection test.  For the next 24 hours, collect all your urine. Your doctor or lab will usually provide you with a large container that holds about 1 gal(3.8 L) and has a small amount of preservative in it. Urinate into a smaller, clean container and then pour the urine into the large container. Avoid touching the inside of the container with your fingers.  Keep the large container in the refrigerator during the collection period.  Empty your bladder for the final time at or just before the end of the 24-hour period. Add this urine to the large container and record the time.  Avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.The skin sweat test for chloride is primarily used to test for cystic fibrosis.How It FeelsBlood testYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain felt depends on the skill ofthe health professional drawing the blood, the condition of your veins, and your sensitivity to pain.Urine testCollecting a 24-hour urine sample does not normally cause discomfort.RisksBlood testThere is very little risk of complications from having blood drawn from a vein. You may develop a small bruise at thepuncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle iswithdrawn.Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usuallytreated with a warm compress applied several times daily. Continued bleeding can be a problem for people withbleeding disorders.Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you havebleeding or clotting problems, or if you take a blood-thinning medication, tell the health professional before your blood isdrawn.Urine testThere are no risks associated with collecting a 24-hour urine sample.ResultsA chloride test measures the level of chloride in your body. Chloride is one of the most important electrolytes in theblood, along with sodium, potassium, and calcium. Chloride helps keep the amount of fluid inside and outside of yourcells in balance.NormalNormal results may vary widely from lab to lab. Blood chloride levels are measured more frequently than urine chloridelevels. ChlorideBlood: 95–103 milliequivalents per liter (mEq/L)
    • Urine: 80–250 mEq/L per 24-hour urine sample (depends heavily upon the amount of salt in the diet)Abnormal values  High blood chloride values can indicate dehydration (such as from diarrhea or vomiting), overactive parathyroid glands (hyperparathyroidism), anemia, or kidney problems.  Low blood chloride levels can indicate excess retention of water, prolonged vomiting, some kidney problems, diabetic ketoacidosis, Cushings syndrome, heart failure, burns, some types of breathing problems, or a syndrome of inappropriate antidiuretic hormone secretion (SIADH), a condition that causes large amounts of fluid to build up in your body.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  The amount of water in your body. If you are dehydrated, your chloride level is increased and if you are overhydrated, your chloride level is decreased.  Medications that increase chloride levels. These include nonsteroidal anti-inflammatory drugs (NSAIDs), estrogens, male hormones (androgens), methyldopa (such as Aldomet), acetazolamide (such as Diamox), cholestyramine (such as Questran), and the hydrochlorothiazide diuretics (such as Esidrix, HydroDIURIL, Oretic).  Medications that decrease chloride levels. These include aldosterone, corticosteroids, medications containing bicarbonate, and furosemide (Lasix).  Potassium chloride (found in salt substitutes), which can lower your blood chloride levels but raise your urine chloride levels.  Failing to collect exactly 24 hours of urine during a 24-hour urine test for chloride.What To Think About  The results from a blood or urine chloride test do not provide enough information to diagnose a specific disease or problem. A diagnosis requires a medical history and physical examination along with other test results.  Tests for sodium, potassium, and bicarbonate usually are done at the same time as a blood test for chloride. For more information, see the medical tests Sodium (Na) in Blood, Potassium (K) in Blood, and Bicarbonate.  The skin sweat test for chloride is primarily used to test for cystic fibrosis. For more information, see the medical test Sweat Test.
    • Alpha-Fetoprotein (AFP) in Blood Test OverviewAn alpha-fetoprotein (AFP) blood test is done to determine the level of AFP in a pregnant womans blood. AFP is asubstance naturally produced by the liver of a fetus. The amount of AFP in the blood of a pregnant woman can helpdiagnose whether the fetus may have such problems as spina bifida, anencephaly, or Down syndrome. An AFP test canalso be done to detect other, more rare conditions, such as chromosome (trisomy) syndromes or omphalocele, acongenital defect in which portions of a fetuss intestines protrude through the abdominal wall.Normally, low levels of AFP can be found in the blood of a pregnant woman. No AFP (or only a very low level) is usuallyfound in the blood of healthy men or healthy, nonpregnant women.The level of AFP in the blood is often used in a maternal serum triple or quadruple screening test. Usually donebetween 16 and 18 weeks, these tests measure the amounts of three or four substances in a pregnant womans blood.The triple screen measures alpha-fetoprotein (AFP), beta human chorionic gonadotropin (beta-HCG), and a type ofestrogen (unconjugated estriol, or uE3). The quad screen measures these substances and the hormone inhibin-A. Thelevels of these substances—along with a womans age and other factors—help estimate the risk that her child may havecertain problems or birth defects.In some cases a combination of screening tests is done in the first trimester to look for Down syndrome. The screeningcombines ultrasound measurement of the thickness of the fetuss neck (nuchal fold) and measurements of beta-HCGand a protein called pregnancy-associated plasma protein A. The accuracy of this screening is about the same as that 1of the second-trimester maternal serum quad screening. Should I have the maternal serum screening test (triple or quad screen)?Men and nonpregnant womenIn men and nonpregnant women, alpha-fetoprotein in the blood can indicate the presence of certain types of cancer,especially cancer of the testicles, ovaries, stomach, pancreas, or liver. Increased levels of AFP may also be found inHodgkins disease, lymphoma, and renal cell cancer.Health ToolsHealth tools help you make wise health decisions or take action to improve your health. Decision Points focus on key medical care decisions that are important to many health problems. Should I have the maternal serum triple or quadruple test (triple or quad screen)?Why It Is DoneThe AFP test is done to:  Screen the fetus of a pregnant woman for brain or spinal problems (called neural tube defects). Such defects occur in about 2 out of every 1,000 pregnancies. The risk of a neural tube defect in a fetus is not related to the mothers age. Most women whose babies have neural tube defects have no family history of similar problems. When used to screen for birth defects, this test should be done between the 15th and 22nd weeks of pregnancy.  Screen the fetus of a pregnant woman for Down syndrome. A low AFP level can detect Down syndrome about 60% of the time. The chance of detecting Down syndrome increases to about 80% when results of the AFP test are considered along with the results from two other tests (estriol and human chorionic gonadotropin). When done together, these three tests are called the triple test.  Diagnose and monitor the effectiveness of treatment for some cancers, especially cancer of the testicles, ovaries, or liver. However, up to half of the people with liver cancer do not have high AFP levels.
    •  Screen for liver cancer (called hepatoma) among people who have cirrhosis or chronic hepatitis B.How To PrepareNo special preparation is required before having this blood test. If you are pregnant, you will be weighed before theblood test because the test results will be based on your weight. This test is also based on race.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the person drawing the blood, the condition of your veins, and your sensitivity to pain.You may feel anxious while awaiting results of an alpha-fetoprotein test done to determine the health of your unbornbaby.RisksRisks of a blood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), heparin, and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsAn alpha-fetoprotein (AFP) blood test is done to determine the level of AFP in a pregnant womans blood. AFP is asubstance naturally produced by the liver of a fetus. The amount of AFP in the blood of a pregnant woman can helpdiagnose certain conditions or diseases in a fetus.NormalNormal alpha-fetoprotein (AFP) values may vary from lab to lab. Also, normal values vary according to the age of thefetus; a high or low AFP may mean that the age of the fetus has been miscalculated. An ultrasound may be done todetermine fetal age more accurately. For more information, see the medical test Fetal Ultrasound. Alpha-fetoprotein in blood Men and nonpregnant women: 0–6.4 international units per milliliter (IU/mL) 0–20 nanograms per milliliter (ng/mL)
    • 0–20 micrograms per liter (µg/L) Women 15–22 weeks pregnant: 19–75 IU/mL 7–124 ng/mL 7–124 µg/LIn pregnant women, the amount of alpha-fetoprotein (AFP) gradually rises starting in the 14th week of pregnancy. Itcontinues to rise until a month or two before giving birth, then it slowly declines. Values are generally slightly higher forblack women than they are for white women. Values are slightly lower for Asian women than they are for white women.An accurate estimate of the age of the fetus is needed to interpret the alpha-fetoprotein value correctly.The normal range of AFP values is adjusted for each womans weight and race, whether she has diabetes (requiringinjections of insulin), and the age of her fetus (gestational age). If the estimated age of the fetus is changed throughultrasound, the AFP must be adjusted. The middle of this adjusted range is called the multiple of median (MOM). AnAFP value that is within 0.5 to 2.5 times the MOM value is considered normal for that woman. Each woman needs tolook at the range of AFP values that is normal for her when she has an AFP test.High values  High alpha-fetoprotein values in a pregnant woman can indicate: o An inaccurate gestational age. o A multiple pregnancy (such as twins, triplets). o A fetus with a neural tube defect. o That the fetuss intestines and other abdominal organs are being formed outside the body (called an abdominal wall defect). Surgery after birth will be needed to correct the defect. o Fetal death.  In a nonpregnant adult, a high alpha-fetoprotein value can indicate cancer of the liver, testicles, or ovaries.  High values can also indicate liver disease, such as cirrhosis or hepatitis.  Alcoholism.Low valuesIn a pregnant woman, a low level of alpha-fetoprotein can mean:  An inaccurate gestational age.  A fetus with Down syndrome.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Smoking, which increases the level of alpha-fetoprotein in the blood.  A medical test in the past 2 weeks that used radioactive tracers.What To Think About  The level of AFP in the blood is often used in maternal serum triple or quadruple screening test. Usually done between 16 and 18 weeks, these tests measure the amounts of three or four substances in a pregnant womans blood. The triple screen measures alpha-fetoprotein (AFP), beta human chorionic gonadotropin (beta-HCG), and a type of estrogen (unconjugated estriol, or uE3). The quad screen measures these substances and the hormone inhibin-A. The levels of these substances—along with a womans age and other factors—help estimate the risk that her child may have certain problems or birth defects. For more information about estriol and hCG, see the medical tests Estrogens and Human Chorionic Gonadotropin (hCG).  AFP is a screening test to look for possible problems in the fetus. Additional testing must always be done if the AFP results are abnormal. An ultrasound will be done to evaluate an abnormal AFP. If an ultrasound cannot detect the cause of the abnormal AFP, an amniocentesis may be done.  Normal AFP results do not rule out a neural tube defect or Down syndrome.  AFP test results are based on the age of the fetus. If a pregnant woman has a high AFP level, ultrasound may be used to estimate the age of the fetus as accurately as possible. An ultrasound often reveals a cause for the elevated AFP levels other than birth defects, such as a multiple pregnancy or
    • underestimated fetal age. An ultrasound may also be done before the AFP test if the age of the fetus is not accurately known. For more information, see the medical test Fetal Ultrasound.  The amount of AFP in the amniotic fluid may also be measured using amniocentesis. Most women have normal AFP levels in the amniotic fluid, even though the levels may be abnormal in their blood. These women are at low risk of having a fetus with a neural tube defect. For more information, see the medical test Amniocentesis.  If abnormal levels of AFP are found in the blood of a pregnant woman, she should discuss the results and further plans with her health professional or genetic counselor. AFP test results can be abnormal, even when nothing is wrong with the fetus. Additional tests, such as amniocentesis, may be done if AFP blood levels are abnormal and ultrasound shows that there is one fetus and the estimated fetal age is correct.  In people with liver cancer or other types of cancer, a decrease in AFP may indicate a favorable response to treatment.ReferencesCitations 1. American College of Obstetricians and Gynecologists (2004). ACOG issues position on first-trimester screening methods. Available online: http://www.acog.org/from_home/publications/press_releases/nr06- 30-04.cfm.
    • Antinuclear Antibodies (ANA) Test OverviewAn antinuclear antibody (ANA) test measures the amount and pattern of abnormal antibody that work against the bodystissues (autoantibody). Everyone has a small amount of autoantibody, but about 5% of people have a larger amount.About half of these 5% have an autoimmune disease, such as systemic lupus erythematosus or rheumatoid arthritis. AnANA test alone cannot diagnose a specific disease. It is used in combination with an evaluation of symptoms and othertests.The bodys immune system normally attacks and destroys foreign substances such as bacteria and viruses. However,in disorders known as autoimmune diseases, the immune system attacks and destroys the bodys normal tissues. Whena person has an autoimmune disease, the immune system produces antibodies that attach to the bodys own cellsas though they were foreign substances, often causing them to be damaged or destroyed. A thorough medical history,physical examination, and other tests besides an ANA test are needed confirm a suspected autoimmune disease.Why It Is DoneA test for antinuclear antibodies (ANA) is done to help diagnose conditions that include:  Systemic lupus erythematosus (SLE).  Rheumatoid arthritis  Sjِ rens syndrome. g  Scleroderma.  Hashimotos thyroid disease.  A reaction to a medication.How To PrepareNo special preparation is required before having this test.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the person drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood test
    • There is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsAn antinuclear antibody (ANA) test measures the amount and pattern of abnormal antibody that work against the bodystissues (autoantibody).The results of an antinuclear antibody (ANA) test are expressed in titers. A titer is a measure of how much the bloodsample can be diluted before the presence of the antibodies can no longer be detected. A titer of 1 to 80 (1:80) meansthat antibodies could be last detected when 1 part of the blood sample was diluted by 80 parts of another liquid (usuallya dilute salt solution). A larger second number indicates that the antibodies are present in greater concentration.Therefore, a titer of 1 to 320 indicates a higher concentration of antibodies in the blood than a titer of 1 to 80.There are different subtypes of ANA which may have a range of normal values.NormalNormal values may vary from lab to lab. Antinuclear antibodiesTiter below 1:20 or 1:40, depending on the test method usedHigh values  A high ANA titer may indicate systemic lupus erythematosus (SLE). SLE can be present with titers from 1 to 40 and higher. Almost all people with SLE have a high ANA titer. However, most people with a high ANA titer do not have SLE. Only about one-third of people who are referred to a rheumatologist for high ANA titers are diagnosed with SLE. Other conditions may cause a high ANA titer. About 30% to 40% of people with rheumatoid arthritis have a high ANA titer.  Many conditions may result in a high ANA titer. These conditions include autoimmune diseases, such as scleroderma, Sjِ rens syndrome, juvenile rheumatoid arthritis, and myositis. Other conditions with a high g ANA titer include Raynauds syndrome, viral infections, and liver disease. Although an ANA titer may help support a diagnosis for these conditions, it is not used by itself to confirm a diagnosis. A thorough medical history, physical examination, and other tests are needed to confirm a suspected autoimmune disease.  Some apparently healthy individuals have high levels of antinuclear antibodies. For instance, some people with a family history of autoimmune disease may have a high ANA titer. The higher the titer, however, the more likely it is that the person has an autoimmune disease.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Medications, such as hydralazine (Apresoline), procainamide (Procan, Pronestyl, Promine), and certain anticonvulsants (such as Dilantin, Mysoline). These medications can cause a form of systemic lupus erythematosus (SLE) called drug-induced lupus. Lupus resulting from these medications may cause a high antinuclear antibody (ANA) titer.  Medications, such as antibiotics (isoniazid, penicillin, and tetracycline), birth control pills, lithium, and some diuretics, such as chlorthalidone (Hygroton).  Heart or blood pressure medications, such as acebutolol (Sectral), captopril (Capoten), atenolol (Tenormin), metoprolol (Lopressor), lovastatin (Mevacor), and quinidine.  Aging. Some older adults (5% to 40%) may have mildly elevated levels. Older women appear to have higher ANA titers than older men.  Steroids, which may cause a false-negative result.
    • What To Think About  The result of an antinuclear antibody (ANA) test is used along with a thorough medical history, physical examination, or other tests to diagnose systemic lupus erythematosus (SLE) or other autoimmune diseases. SLE cannot be diagnosed by the results of the ANA test alone.  Some healthy people can have an elevated ANA titer. Also, ANA levels can increase with age.  A method to detect antinuclear antibodies called enzyme-linked immunosorbent assay (ELISA) is replacing the previous method of testing (immunofluorescent assay technique, or IFA). The ELISA method is less likely to produce a false-positive ANA result than the IFA method.
    • Lactic acid dehydrogenase (LDH) Exam OverviewLactic acid dehydrogenase (LDH) is an enzyme that helps produce energy. It is present in almost all of the tissues in thebody and becomes elevated in response to cell damage. LDH levels are measured from a sample of blood taken from avein.Why It Is DoneLDH levels help diagnose heart attack, lung disease, lymphoma, anemia, and liver disease. They also help determinehow well chemotherapy is working during treatment for lymphoma.ResultsNormal LDH levels range from 45 units per liter (U/L) to 90 U/L.What To Think AboutMany diseases can cause elevations in LDH levels. Other tests are usually needed to confirm a diagnosis.If heart attack is suspected, the LDH levels will be rechecked at 24 and 48 hours to monitor for changes.
    • Creatine Kinase (CK) Creatine kinase is an enzyme that catalyzes the reversible phosphorylation of creatine by ATP. The end product, phosphocreatine, is a readily available energy source for cells. CK is present in many tissues butskeletal and heart muscles contain the highest concentrations. CK released from skeletal muscle accounts for almost all of the CK activity detected in the plasma of healthy individuals. Circulating CK is cleared by degradation in the liver and reticuloendothelial system and has a circulating half-life of 12 hours. Historically, CK has been used most often measured to diagnose acute myocardial infarction. Serum CK increases 4 to 6 hours after myocardial necrosis and remains elevated 24 to 48 hours post infarction. Serial measurement of CK activity at 0, 6, and 12 hours after the onset of chest pain yields the greatest sensitivity and specificity (See Cardiac Marker History). In May 2001, the American College of Cardiologists recommmended that total CK no longer be included as a cardiac marker.Plasma CK levels are helpful in diagnosing rhabdomyolysis, because objective clinical signs are often absent.CK is a more sensitive marker of skeletal muscle injury than urine myoglobin. CK levels may exceed 100,000 U/L. CK levels above 6000 U/L are associated with an increased risk of acute tubular necrosis.Chronic muscle disease, such as the muscular dystrophies and polymyositis- dermatomyositis, elevate plasma CK levels, but not to the same extent as rhabdomyolysis. Muscle trauma and burns also significantly elevate CK. Intramuscular injections and noncardiac surgery elevate total CK. Plasma CK activity is not usually elevated by mild exercise, unless a person is in poor physical conditioning. Severe or prolonged exercise can increase CK levels. The normal range is very broad skewed toward the top end. Age, sex, and race affect the reference interval.CK levels decline with age due to a reduction in muscle mass. Black men have higher CK levels than non-black men or black women, who have higher levels than white or Asian women. Differences in muscle mass are believed to account for these sex and racial differences. Basal CK levels are higher in the physically fit, reflecting their greater muscle mass. Some patients may have subnormal CK levels, which may result from reduced muscle mass due to aging, wasting or cachexia. Another explanation is decreased physical activity caused by illness or advanced age. Alcoholics often have low CK levels due to reduced muscle mass. Patients with viral hepatitis may have low levels from reduced physical activity. Some patients with connective tissue disease have low CK activity, butthe mechanism is unknown. Patients with thyrotoxicosis and Cushings disease frequently have low plasma CK activity, presumably due to altered membrane permeability and diminished enzyme efflux . A similar mechanism may be responsible for the subnormal enzyme activity in patients receiving steroids, estrogens, oral contraceptives, and tamoxifen. Captopril, an antihypertensive drug, produces low plasma CK levels byinterfering with disulfide bond formation. Patients with septicemia often have low CK levels due to glutathione depletion, which is necessary for preservation of enzyme activity in the plasma. Reference range is 30 - 225 IU/mL (Vitros Analyzer). Specimen requirement is one SST tube.
    • Creatine Kinase MB (CK-MB)Creatine kinase is composed of two subunits, CK-M (muscle type) and CK-B (brain type), which are combined into three distinct isoenzymes: CK-MM, CK-MB, and CK-BB. The following table illustrates the isoenzyme composition of different tissues. Tissue CK-MM CK-MB (%) CK-BB (%) (%) Brain 0 0 100 Heart 80 20 trace Skeletal 99 1 0 muscle The skeletal muscle of marathon runners may contain up to 8% CK-MB. CK-MB is a more sensitive marker of myocardial injury than total CK activity, because it has a lower basal level and a much narrower normal range. Medical literature commonly states that CK-MB levels become elevated in 4 to 6 hours, peak at 10 to 24 hours, and return to normal within 3 to 4 days after an acute myocardial infarction. However, these enzyme kinetics were determined using an insensitive electrophoretic method. In 1991, most laboratories began measuring CK-MB mass instead of enzyme activity. CK-MB massassays are able to measure small, but significant changes during the early hours following onset of chest pain. In 1995, a study of 225 consecutive patients admitted to a Midwestern hospital for evaluation of acute myocardial infarction were reviewed to determine how quickly CK-MB becomes positive. Time of Positive CK- Number of MB Cases O hours 31 6 hours 14 12 hours 2 24 hours 2Forty nine of the 225 patients had elevated CK-MBs. Interestingly, 45 of the 49 (92%) were detected within 6hours; only 4 CK-MBs turned positive at 12 or 24 hours. In an additional 13 cases, the 24 hour specimen was canceled because the patient had already been discharged. The laboratory frequently encounters patients in which the CK-MB is elevated above 6 ng/mL, but the total creatine kinase (CK) is within normal limits (30 - 225 U/L). To determine if these results are clinically significant, the medical records of 85 consecutive patients were reviewed between February and April, 1995.Ten patients were discharged before the clinical outcome could be determined. The remaining 75 patients had the following diagnoses.
    • Diagnosis # Patients Myocardial infarction 30 Unstable angina 15 Open heart 12 surgery/angioplasty Other heart diseases 10 Other diseases 8Other heart diseases included 3 cases of atrial fibrillation, 3 cor pulmonale, 2 cardiomyopathies, 1 aortic valve stenosis, and 1 angina. Other diseases included 3 cases of CNS hemorrhage, 3 pneumonias, 1 bacteremia,and 1 transient ischemic attack with carotid endarterectomy. These results demonstrated that at least 60% of the patients with normal total CK and elevated CK-MB had suffered myocardial damage. Based on these findings, CK-MB should be ordered in symptomatic patients even if total CK is not elevated. Reference range is 0 - 5 ng/mL. Specimen requirement is one SST tube of blood.
    • Creatinine Kinase Isoenzymes Creatine kinase (CK) is an enzyme that catalyzes the reversible phosphorylation of creatine by ATP. The end product, phosphocreatine, is a readily available energy source for cells. CK is present in many tissues but skeletal and heart muscles contain the highest concentrations. CK released from skeletal muscle accounts for almost all of the CK activity detected in the plasma of healthy individuals. Circulating CK is cleared bydegradation in the liver and reticuloendothelial system and has a circulating half-life of 12 hours. Occasionally, measurement of CK isoenzymes may be helpful in elucidating the origin of an unexplained or persistently elevated total CK. CK is composed of two subunits, CK-M (muscle type) and CK-B (brain type), which are combined into three distinct isoenzymes: CK-MM, CK-MB, and CK-BB. These isoenzymes can be separated and measured by electrophoresis. The following table illustrates the isoenzyme composition of different tissues. Tissue CK-3 (MM) CK-2 (MB) CK- 1 (BB) (%) (%) (%) Brain 0 0 100 Heart 60-80 20-40 0 Skeletal 96-100 0-4 0 muscleBrain tissue contains predominantly CK1 (BB) and skeletal muscle contains almost exclusively CK3 (MM). The myocardium contains approximately 70% of CK3 (MM) and 30% of CK2 (MB). CK-1 (BB) can be elevated in patients with head injury, in neonates, and in some cancers such as prostate cancer and small cell carcinoma of the lung. CK-2 (MB) appears in serum 4 to 6 hours after the onset of pain in an MI, peaks at 18 to 24 hours, and returns to normal by 72 hours. CK-MB may also be elevated in cases of carbon monoxide poisoning, pulmonary embolism, hypothyroidism, crush injuries, and muscular dystrophy. Extreme elevations of CK-MB can be associated with skeletal muscle cell turnover as in polymyositis, and to a lesser degree in rhabdomyolysis. Besides the 3 CK isoenzymes, electrophoresis can also detect 2 types of macro-CK. Macro-CK Type I is a complex of immunoglobulin, usually IgG, and CK-BB that migrates between CK-MM and CK-MB. It occursprimarily in elderly women and causes a persistent elevation of plasma CK activity because the large complex is not cleared. Macro-CK Type II represents Mitochondrial CK that migrates slightly cathodic of MM. It is usually only detected in severely ill patients with liver disease, malignancies or hypoxic injury.
    • Cardiac Enzyme Studies Test OverviewCardiac enzyme studies measure the levels of the enzymes troponin (TnI, TnT) and creatine phosphokinase (CPK, CK)in the blood. Low levels of these enzymes are normally found in your blood, but if your heart muscle is injured, such asfrom a heart attack, the enzymes leak out of damaged heart muscle cells and their levels in the bloodstream rise.Because some of these enzymes are also found in other body tissues, their levels in the blood may rise when thoseother tissues are damaged. Cardiac enzyme studies must always be compared with your symptoms, your physicalexamination findings, and electrocardiogram (EKG, ECG) results.Why It Is DoneCardiac enzyme studies are done to:  Determine whether you are having a heart attack or a threatened heart attack (unstable angina) if you have chest pain, shortness of breath, nausea, sweating, and abnormal electrocardiography results.  Check for injury to the heart after bypass surgery.  Determine if a procedure, such as percutaneous coronary intervention (PCI), or a medicine to dissolve the blockage (thrombolytic medicine) has successfully restored blood flow through a blocked coronary artery.How To PrepareNo special preparation is required before having this test.Many medicines may affect the results of this test. Be sure to tell your health professional about all the nonprescriptionand prescription medicines you take.Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or whatthe results will indicate. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).How It Is DoneThe health professional drawing your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Put a gauze pad or cotton ball over the needle site as the needle is removed.  Put pressure on the site and then put on a bandage.Cardiac enzyme studies are often repeated over several hours for comparison. Blood samples for these cardiac enzymetests are usually drawn every 8 to 12 hours for 1 to 2 days after a suspected heart attack, to look for the rise and fall inthe enzyme levels.How It Feels
    • The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight.You may feel nothing at all from the needle, or you may feel a quick sting or pinch.RisksThere is very little chance of a problem from having blood sample taken from a vein.  You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.  In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.  Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin) and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.ResultsCardiac enzyme studies measure the levels of the enzymes troponin (TnI, TnT) and creatine phosphokinase (CPK, CK)in the blood.Test results are usually available within an hour.Values and units for reporting the results of cardiac enzyme tests vary considerably from lab to lab. The values listedbelow can be used as a general guide. Check with your lab or doctor for specific values. Troponin (TnI and TnT) Normal: TnI: Less than 0.3 micrograms per liter (µg/L) TnT: Less than 0.1 µg/L Abnormal: Elevated troponin may be present when you have heart muscle injury. Blood levels of troponin typically rise within 4 to 6 hours after a heart attack, reach their highest levels within 10 to 24 hours, and fall to normal levels within 10 days. Total CPK (creatine phosphokinase) Normal: Men: 55–170 international units per liter (IU/L) Women: 30–135 IU/L Abnormal: CPK levels generally rise within 4 to 8 hours after a heart attack, peak within 12 to 24 hours, then return to normal within 3 to 4 days. CPK-MB Normal: Less than 3.0 nanograms per milliliter (ng/mL) (0% of total CPK) Abnormal: CPK-MB is found in large amounts in the heart muscle. A CPK-MB greater than 3.0 ng/mL may be present when you have muscle damage caused by a heart attack. Blood levels of CPK-MB typically rise within 2 to 6 hours after a heart attack, reach their highest levels within 12 to 24 hours, and fall to normal levels within 3 days. An ongoing high level of CPK-MB levels after 3 days may mean that a heart attack is progressing and more heart muscle is being damaged.What Affects the Test
    • Reasons you may not be able to have the test or why the results may not be helpful include:  Other diseases, such as muscular dystrophy, certain autoimmune diseases, and Reyes syndrome.  Other heart conditions, such as myocarditis and some forms of cardiomyopathy.  Emergency measures to treat heart problems, such as CPR, cardioversion, or defibrillation.  Medicines, especially injections into muscles (IM injections).  Cholesterol-lowering medicines (statins).  Heavy alcohol use.  Recent strenuous exercise.  Kidney failure.  Recent surgery or serious injury.What To Think About  Cardiac enzyme levels must always be compared with your symptoms, medical history, physical examination, and electrocardiography (EKG, ECG) results.  Troponin is an accurate method for quickly diagnosing heart attack, but because it takes up to 6 hours to rise, it can be low or negative at first. Troponin is more specific to heart muscle and remains in the bloodstream longer than CPK.  CPK-MB, which is found only in heart muscle, is a more specific way to estimate the amount of heart muscle damage than total CPK. The total CPK enzyme level can be elevated from vigorous exercise, intramuscular injections, crush injuries to muscles, muscular dystrophy, or muscle inflammation.  Another enzyme, myoglobin, may be tested along with cardiac enzymes to diagnose a heart attack.ReferencesOther Works Consulted  Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.  Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.  Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.  Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.
    • Lung Biopsy Test OverviewA lung biopsy removes a small piece of lung tissue which can be looked at under a microscope. The biopsy can bedone in 4 ways. The method used depends on where the sample will be taken from and your overall health.  Bronchoscope biopsy. This type of biopsy uses a lighted instrument (bronchoscope) inserted through the mouth or nose and into the airway to remove a lung tissue sample. This method may be used if an infectious disease is suspected, if the abnormal lung tissue is located next to the breathing tubes (bronchi), or before trying more invasive methods, such as an open lung biopsy.  Needle biopsy. A needle biopsy uses a long needle inserted through the chest wall to remove a sample of lung tissue. This method is used if the abnormal lung tissue is located close to the chest wall. A computed tomography (CT) scan, an ultrasound, or fluoroscopy are usually used to guide the needle to the abnormal tissue.  Open biopsy. An open biopsy uses surgery to make an incision between the ribs and remove a sample of lung tissue. An open biopsy is usually done when the other methods of lung biopsy have not been successful, cannot be used, or when a larger piece of lung tissue is needed for a diagnosis.  Video-assisted thorascopic surgery (VATS). A VATS uses a scope (called a thorascope) passed through a small incision in the chest to remove a sample of lung tissue.Why It Is DoneA lung biopsy is done to:  Diagnose certain lung conditions, such as sarcoidosis or pulmonary fibrosis. In rare cases, a lung biopsy may be done for severe pneumonia, especially if the diagnosis is not clear.  Diagnose suspected lung cancer.  Evaluate any abnormalities seen on other tests, such as a chest X-ray or a CT scan. A lung biopsy is usually done when other tests cannot identify the cause of lung problems.How To PrepareYou will be asked to sign a consent form before a lung biopsy. Talk to your doctor about any concerns you haveregarding the need for the biopsy, its risks, how it will be done, or what the results will indicate. To help you understandthe importance of the biopsy, fill out the medical test information form (What is a PDF document?).Before you have a lung biopsy, tell your doctor if you:  Are taking any medications.  Are allergic to any medications, including anesthetics.  Have had bleeding problems or take blood-thinners, such as aspirin or warfarin (Coumadin).  Are or might be pregnant.Your doctor may order certain blood tests, such as a complete blood count (CBC) and bleeding factors, before your lungbiopsy.Do not eat or drink for 8 to 10 hours before the biopsy.Arrange to have someone drive you home after the procedure if you do not need to stay in the hospital.How It Is DoneYou may be given some medications before the biopsy to dry up the secretions in your mouth and airways.
    • A needle or bronchoscope biopsy can be done without staying in the hospital. An open biopsy requires a hospital stayfor at least a few days.You may be asked to remove dentures, eyeglasses or contact lenses, hearing aids, wigs, makeup, and jewelry beforethe biopsy. You will empty your bladder before the biopsy. You will need to take off all or most of your clothes (you maybe allowed to keep on your underwear if it does not interfere with the biopsy). You will be given a cloth or papercovering to use during the biopsy.Bronchoscope biopsyA bronchoscope biopsy is done by a doctor who specializes in lung problems (pulmonologist). It is usually done using athin, flexible bronchoscope. In rare cases, a biopsy may be done using a rigid bronchoscope.Bronchoscopy usually takes between 30 and 60 minutes. You will be in the recovery room 1 to 2 hours.Needle biopsyA needle biopsy is done by a doctor who specializes in X-ray tests (radiologist) or a pulmonologist. Your doctor will usea CT scan, ultrasound, or fluoroscopy to guide the biopsy needle. The place where your doctor inserts the needle iscleaned first with an antiseptic solution and draped with sterile towels. Your doctor will give you a local anesthetic tokeep you from feeling any pain when the needle is inserted into your chest.Your doctor will then make a small puncture and ask you to hold your breath while the biopsy needle is inserted intoyour lung. It is very important to avoid coughing or moving while the needle is in your chest.Once the desired amount of tissue is collected, the needle is removed and a bandage is placed over the puncture site.You will need to lie on your side for at least an hour to allow the needle puncture site to seal up.This biopsy takes about 30 to 60 minutes. You will be in the recovery room 1 to 2 hours.Open biopsy and video-assisted thorascopic surgery (VATS)An open biopsy is done by a chest (thoracic) surgeon or a general surgeon. You will be given a general anesthetic byan anesthesiologist. There may also be one or more assistants in the room.You will be given a sedative to help you relax about an hour before the biopsy. You will have an intravenous line (IV)placed in a vein. A tube will be placed in your windpipe (trachea) and a machine will help you breathe.An incision is made between the ribs over the area of lung where the tissue sample is to be collected. A scope called athorascope may be passed through this incision to view the surface of the lung and to remove a sample of lung tissue. Alarger incision will be made if an open biopsy is needed to remove a tissue sample.After the tissue sample is collected, your doctor will insert a drainage tube (chest tube ) into the area and close theincision with stitches. One end of the tube will be in the space next to your lung and the other end will be sticking out ofyour chest and connected to a collection container. The chest tube helps reexpand your lung. The chest tubes will beremoved when the drainage from your chest has stopped and no air is leaking from your chest incision, usually in a fewdays. Your stitches will be removed in 7 to 14 days.The entire biopsy usually takes about an hour. After the lung biopsy is done, you will be taken to the recovery room forabout an hour. You will then be taken to your hospital room.A chest X-ray is usually taken after a lung biopsy to look for any problems related to the biopsy.How It FeelsBronchoscope biopsyThe local anesthetic used in your mouth or nose generally tastes bitter and may make you choke. Your mouth may feelvery dry for several hours after the biopsy. You may also have a sore throat and some hoarseness for a few hours.Sucking on throat lozenges or gargling with warm salt water may help your sore throat.You may have a mild fever shortly after the biopsy, which usually goes away within 24 hours. If it does not, call yourdoctor.
    • Needle biopsyWhen you are given the shot to numb your skin at the needle biopsy site, you will feel a sharp stinging or burningsensation that lasts a few seconds. When the needle is inserted into the chest, you will again feel a sharp pain for a fewseconds. The radiologist may ask you to hold your breath for a few seconds at different times during the biopsy.Open biopsyThe sedative will make you feel sleepy and relaxed. You will be asleep during the biopsy because of the generalanesthetic.After the biopsy, you may feel tired for 1 or 2 days or have general muscle aches. You may also have a mild sore throatfrom the tube that was placed in your throat to help you breathe. Sucking on throat lozenges or gargling with warm saltwater may help your sore throat.You may feel some discomfort at the biopsy site when you take a deep breath. The incision may itch for 3 to 4 days.Your doctor will give you pain medication.A bandage will be placed over the biopsy site. You may be advised to keep the biopsy site covered and dry for 48hours. You may have a small amount of bleeding from the biopsy site. Ask your doctor how much bleeding to expect.RisksA lung biopsy is generally a safe procedure. Any risk depends on if you have a lung disease and how severe it is. If youalready have severe breathing problems, your breathing may be worse for a short time after the biopsy.Bronchoscope and needle biopsies are usually safer than open or VATS biopsies, but the VATS and open biopsies aremore likely to allow a good sample of lung to be removed. A good sample helps determine what the lung problem is andwhat treatment choices are. Bronchoscope or needle biopsies do not need general anesthesia, cause fewer problems,and you do not need to stay overnight in the hospital. Your doctor will discuss any risks with you.  Lung biopsy may increase your chance of developing a collapsed lung (pneumothorax) during the biopsy. Your doctor may need to place a tube in your chest to keep your lung inflated while the biopsy site heals.  Severe bleeding (hemorrhage) may occur.  An infection such as pneumonia may occur, but usually such infections can be treated with antibiotics.  Spasms of the bronchial tubes can occur, which can cause breathing difficulties right after the biopsy.  Irregular heart rhythms (arrhythmias) can occur.  If you receive general anesthesia, there is a small chance of death from complications associated with general anesthesia. However, this is very rare.After the biopsyAfter a lung biopsy, call your doctor immediately if you have:  Severe chest pain.  Lightheadedness.  Difficulty breathing.  Excessive bleeding through the bandage.  Coughed up more than a tablespoon of blood.  A fever.ResultsA lung biopsy removes a small piece of lung tissue which can be looked at under a microscope.Lung biopsy results are usually available in 2 to 4 days. It may take several weeks to get results from tissue samplesthat are being tested for certain infections, such as tuberculosis. Lung biopsy Normal: The lung tissue is normal under a microscope. No signs of infection, inflammation, or cancer are present.
    • Abnormal: Abnormal cells and tissue in the lung may be due to active infection, certain lung diseases, or several different types of cancer. If lung cancer is present, results of the biopsy can determine treatment options (surgery, radiation, or chemotherapy).What Affects the TestA biopsy sample that is too small for a diagnosis can affect the accuracy of the results.A needle biopsy collects tissue from such a small area that there is a chance that a cancer may be missed.What To Think About  Before a final diagnosis is made, the results of a lung biopsy will be considered along with your medical history, physical examination, and the results of other tests, including a chest X-ray or a computed tomography (CT) scan. A bronchoscopy may also be helpful. For more information, see the medical tests Chest X-ray, CT Scan, and Bronchoscopy.  A lung biopsy may not be done for people who have: o Advanced lung disease, such as emphysema. o Bleeding disorders. o Heart failure, high blood pressure in the lungs (pulmonary hypertension), or enlargement of the right side of the heart (cor pulmonale).  Recovery from a video-assisted thorascopic surgery (VATS) takes less time than from an open biopsy surgery.
    • Lung Function Tests Test OverviewLung function tests (also called pulmonary function tests, or PFTs) evaluate how well your lungs work. The testsdetermine how much air your lungs can hold, how quickly you can move air in and out of your lungs, and how wellyour lungs add oxygen and remove carbon dioxide from your blood. The tests can diagnose lung diseases and measurethe severity of lung problems.Spirometry is the first lung function test done. It measures how much and how quickly you can move air out of yourlungs. For this test, you breathe into a mouthpiece attached to a recording device (spirometer). The informationcollected by the spirometer may be printed out on a chart called a spirogram.The more common lung function values measured with spirometry are:  Forced vital capacity (FVC). This measures the amount of air you can exhale with force after you inhale as deeply as possible.  Forced expiratory volume (FEV). This measures the amount of air you can exhale with force in one breath. The amount of air you exhale may be measured at 1 second (FEV 1), 2 seconds (FEV2), or 3 seconds (FEV3). FEV1 divided by FVC can also be determined.  Forced expiratory flow 25% to 75%. This measures the air flow halfway through an exhale (FVC).  Peak expiratory flow (PEF). This measures how quickly you can exhale. It is usually measured at the same time as your forced vital capacity (FVC).  Maximum voluntary ventilation (MVV). This measures the greatest amount of air you can breathe in and out during one minute.  Slow vital capacity (SVC). This measures the amount of air you can slowly exhale after you inhale as deeply as possible.  Total lung capacity (TLC). This measures the amount of air in your lungs after you inhale as deeply as possible.  Functional residual capacity (FRC). This measures the amount of air in your lungs at the end of a normal exhaled breath.  Residual volume (RV). This measures the amount of air in your lungs after you exhale with force.  Expiratory reserve volume (ERV). This measures the difference between the amount of air in your lungs after a normal exhale (FRC) and the amount after you exhale with force (RV).Other tests such as residual volume, gas diffusion tests, body plethysmography, inhalation challenge tests, and exercisestress tests may also be done to determine lung function.Residual volume (RV)Residual volume, or the amount of air that remains in your lungs after you exhale as completely as possible, ismeasured with gas dilution tests. You breathe a known amount of a gas (either 100% oxygen or a certain amount ofhelium in air) from a container. The test measures how the concentration of the gases in the container changes.Gas diffusion testsGas diffusion tests measure the amount of oxygen and other gases that cross the lungs air sacs (alveoli ) perminute. These tests evaluate how well gases are being absorbed into your blood from your lungs. Gas diffusion testsinclude:  Arterial blood gases, which determine the amount of oxygen and carbon dioxide in your bloodstream.  Carbon monoxide diffusing capacity (also called transfer factor, or TF), which measures how well your lungs transfer a small amount of carbon monoxide (CO) into the blood. Two different methods are used for this test. If the single-breath or breath-holding method is used, you will take a breath of air containing a very small amount of carbon monoxide from a container while measurements are taken. In the steady- state method, you will breathe air containing a very small amount of carbon monoxide from a container.
    • The amount of carbon monoxide in your arterial blood is then measured. Diffusing capacity provides an estimate of how well a gas is able to move from your lungs into your blood.Body plethysmographyBody plethysmography measures the total amount of air your lungs can hold (total lung capacity, or TLC). For this test,you sit inside an airtight booth called a plethysmograph and breathe through a mouthpiece while pressure and air flowmeasurements are collected.Inhalation challenge testsInhalation challenge tests are done to identify substances (allergens) that may be causing severe respiratory allergies orasthma. These tests are also called provocation studies.During inhalation testing, increasing amounts of an allergen are inhaled through a nebulizer, a device that uses a facemask or mouthpiece to deliver the allergen in a fine mist (aerosol). Alternatively, increasing amounts of a substance(histamine or methacholine) may be inhaled through the nebulizer. Before and after inhaling the substance, spirometryreadings are taken to evaluate lung function.In rare cases, a bronchospasm can occur with inhalation challenge testing. You will be closely monitored during andafter the test.Exercise stress testsExercise stress tests evaluate the effect of exercise on lung function tests. Spirometry readings are done after exerciseand then again at rest.Lung function results are measured directly in some tests and are calculated in others. No single test can determine allof the lung function values, so more than one type of test may be done. Some of the tests may be repeated after youinhale medication that enlarges your airways (bronchodilator).Why It Is DoneLung function tests are done to:  Determine the cause of breathing problems.  Diagnose certain lung diseases, such as asthma or chronic obstructive pulmonary disease (COPD).  Evaluate a persons lung function before surgery.  Monitor the lung function of a person who is regularly exposed to substances such as asbestos or radon that can damage the lungs.  Monitor the effectiveness of treatment for lung diseases.How To PrepareTell your doctor if you:  Have had recent chest pains or a heart attack.  Take medication for a lung problem, such as asthma. You may need to stop taking some medications before testing.  Are allergic to any medications.Do not eat a heavy meal just before this test because a full stomach may prevent your lungs from fully expanding. Youshould not smoke or exercise strenuously for 6 hours before the test. On the day of the test, wear loose clothing thatdoes not restrict your breathing in any way.If you have dentures, wear them during the test to help you form a tight seal around the mouthpiece of the spirometer.How It Is DoneLung function tests are usually done in special exam rooms that have all of the lung function measuring devices. Thetest is usually done by a specially trained respiratory therapist or technician. For most of the lung function tests, you willwear a nose clip to make sure that no air passes in or out of your nose during the test. You then will be asked to breatheinto a mouthpiece connected to a recording device.
    • The exact procedure is different for each type of test. For example, you may be asked to inhale as deeply as possibleand then to exhale as fast and as hard as possible. You also may be asked to breathe in and out as deeply and rapidlyas possible for 15 seconds. Some tests may be repeated after you have inhaled a spray containing medication thatexpands the airways in your lungs (bronchodilator). You may be asked to breathe a special mixture of gases, such as100% oxygen, a mixture of helium and air, or a mixture of carbon monoxide and air. Sometimes a sample of blood maybe taken from an artery in your wrist to measure blood gases.If you have body plethysmography, you will be asked to sit inside a small enclosure similar to a telephone booth, withwindows that allow you to see out. The booth measures small changes in pressure that occur as you breathe.The accuracy of the tests depends on your ability to follow all of the instructions. The therapist may strongly encourageyou to breathe deeply during some of the tests to get the best results.The testing may take from 5 to 30 minutes, depending upon how many tests are done.How It FeelsIf you have an arterial blood gas test, you may feel some pain from the needle used to collect the blood. The other lungfunction tests are usually painless. Some of the tests may be tiring for people who have a lung disease.You may cough or feel lightheaded after breathing in or out rapidly, but you will be given a chance to rest between tests.You may find it uncomfortable to wear the nose clip. Breathing through the mouthpiece for a long period of time may beuncomfortable.If you have body plethysmography, you may feel uncomfortable in the airtight plethysmograph booth. However, thetherapist will be nearby during the test to open the door if you feel too uncomfortable.If you are given breathing medication, it may cause you to shake or may increase your heart rate. If you feel any chestpain or discomfort, tell the therapist immediately.RisksLung function tests present little or no risk to a healthy person. If you have a serious heart or lung condition, discussyour risks with your doctor.ResultsLung function tests (also called pulmonary function tests, or PFTs) evaluate how well your lungs work. The normal valueranges for lung function tests will be adjusted for your age, height, sex, and sometimes weight and race. Results areoften expressed in terms of a percentage of the expected value.NormalTest results are within the normal ranges for a person with healthy lungs.AbnormalThere are two main types of lung disease that can be found with lung function tests: obstructive and restrictive.ObstructiveIn obstructive lung conditions, the airways are narrowed, usually causing an increase in the time it takes to empty thelungs. Obstructive lung disease can be caused by conditions such as emphysema, bronchitis, infection (which producesinflammation), and asthma. Lung function test Result as predicted for age, height, sex, weight, or race Forced vital capacity (FVC) Normal or lower than predicted value Forced expiratory volume (FEV1) Lower with higher FEV2 and FEV3 FEV1 divided by FVC Lower Forced expiratory flow 25% to 75% Lower Peak expiratory flow (PEF) Lower
    • Maximum voluntary ventilation (MVV) Lower Slow vital capacity (SVC) Normal or lower Total lung capacity (TLC) (VT) Normal or higher Functional residual capacity (FRC) Higher Residual volume (RV) Higher Expiratory reserve volume (ERV) Normal or lower RV divided by TLC ratio HigherFEV1 often increases after using medication that expands the airways in people with reversible obstructive disease likeasthma.RestrictiveIn restrictive lung conditions, there is a loss of lung tissue, a decrease in the lungs ability to expand, or a decrease inthe lungs ability to transfer oxygen to the blood (or carbon dioxide out of the blood). Restrictive lung disease can becaused by conditions such as pneumonia, lung cancer, scleroderma, pulmonary fibrosis, sarcoidosis, or multiplesclerosis. Other restrictive conditions include some chest injuries, being very overweight (obesity), pregnancy, and lossof lung tissue due to surgery. Lung function test Result as predicted for age, height, sex, weight, or race Forced vital capacity (FVC) Lower than predicted value Forced expiratory volume (FEV1) Normal or lower with higher FEV2 and FEV3 FEV1 divided by FVC Normal or higher Forced expiratory flow 25% to 75% Normal or lower Peak expiratory flow (PEF) Normal or higher Maximum voluntary ventilation (MVV) Normal or lower Slow vital capacity (SVC) Lower Total lung capacity (TLC) (VT) Lower Functional residual capacity (FRC) Normal or higher Residual volume (RV) Normal or higher Expiratory reserve volume (ERV) Normal or lower RV divided by TLC ratio Normal or higherPEF is usually normal in restrictive lung disease unless the disease is severe.What Affects the TestFactors that can interfere with your test or the accuracy of the results include:  Using medication that expands the lungs airways within 4 hours of the test.  Using sedatives before the test.  Not being able to breathe normally because of pain.  Pregnancy, obesity, or an enlarged stomach (after a large meal, for example).  Being able to follow instructions and give some effort to the tests.What To Think About  Spirometry is the most commonly used lung function test.  If your spirometry tests are normal but your doctor thinks you may have asthma, additional tests may be done after you inhale a substance (methacholine or histamine) that narrows (constricts) your airways. This is called a bronchoprovocation test. It may be done while you sit in a small enclosure (plethysmograph) similar to a telephone booth. The amount of narrowing in your airways can help diagnose some conditions. This testing may take as long as 2 hours.  Arterial blood gases (ABGs), which determine the amount of oxygen and carbon dioxide in your bloodstream, may be measured before, during, or after your lung function tests. For more information, see the medical test Arterial Blood Gases.
    •  Some lung function tests can be done at home. For more information, see the medical test Home Lung Function Test. Allergy Tests Test OverviewAllergy testing involves having a skin or blood test to determine what substance, or allergen, may trigger an allergicresponse in a person. Skin tests are usually done because they are rapid, reliable, and generally less expensive thanblood tests, but either type of test may be used.Skin testsA small amount of a suspected allergen is placed on or below the skin to see if a reaction develops. There are 3 typesof skin tests:  Skin prick test. This test is done by placing a drop of a solution containing a possible allergen on the skin, and a series of scratches or needle pricks allows the solution to enter the skin. If the skin develops a red, raised itchy area (called a wheal), it usually means that the person is allergic to that allergen. This is called a positive reaction.  Intradermal test. During this test, a small amount of the allergen solution is injected into the skin. An intradermal allergy test may be done when a substance does not cause a reaction in the skin prick test but is still suspected as an allergen for that person. The intradermal test is more sensitive than the skin prick test but is more often positive in people who do not have symptoms to that allergen (false-positive test results).  Skin patch test. For a skin patch test, the allergen solution is placed on a pad that is taped to the skin for 24 to 72 hours. This test is used to detect a skin allergy called contact dermatitis.Blood testAllergy blood tests look for substances in the blood called antibodies. Blood tests are not as sensitive as skin tests butare often used for people who are not able to have skin tests.The most common type of blood test is called radioallergosorbent testing (RAST). It is used to measure the blood levelof a type of antibody (called immunoglobulin E, or IgE) that the body may produce in response to particular allergens.IgE levels are often higher in people who have allergies or asthma. RAST may be used for people who cannot have skintests, such as people who take certain medications (such as some antidepressants) that make the results of skin testsless accurate.Other laboratory testing methods, such as an immunoassay capture test (ImmunoCAP, UniCAP, or Pharmacia CAP),may be used by your health professional to provide additional information.Your allergy test results may show that allergy treatment is a choice for you. For more information, see: Should I have allergy shots (immunotherapy) for allergic rhinitis and allergic asthma?Health ToolsHealth tools help you make wise health decisions or take action to improve your health.Why It Is DoneAllergy testing is done to find out what substances (allergens) cause an allergic reaction.Skin testThe skin prick test can also be done to:  Identify inhaled (airborne) allergens, such as trees, shrubs, weeds, molds, dust, feathers, and pet dander.  Identify likely food allergens (such as eggs, milk, peanuts, nuts, fish, soy, wheat, or shellfish).  Determine whether a person may be allergic to a medication or insect venom.
    • Blood testA blood test on a blood sample may be done instead of a skin prick test if a person:  Has hives or another skin condition, such as eczema, that makes it hard to see the results of skin testing.  Cannot stop taking a medication, such as an antihistamine or tricyclic antidepressant, that may prevent or reduce a reaction to a substance even when a person is allergic to the substance.  Has had a severe allergic reaction (anaphylaxis).  Has had positive skin tests to many foods. Radioallergosorbent testing (RAST) can determine the foods to which a person is most allergic.How To PrepareMany medications can affect the results of this test. Be sure to tell your health professional about all the nonprescriptionand prescription medications you take. You may need to stop taking some medications, such as some tricyclicantidepressants and antihistamines such as cetirizine (Zyrtec), fexofenadine (Allegra), and loratadine (Claritin) beforeyou have an allergy skin test.Tricyclic antidepressants and antihistamines have no effect on radioallergosorbent test (RAST) results. However, youshould not have a radioactive scan (such as a bone or thyroid scan) within a week before a scheduled RAST.Do not drink alcohol or beverages containing caffeine before you have a RAST. You do not need to restrict foods orother fluids before skin test or a RAST.Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).How It Is DoneSkin testsThe health professional doing the skin prick or intradermal test will:  Clean the test site (usually on your back or arm) with alcohol.  Place drops of the possible allergens on your skin about 1 in.(2.5 cm) to 2 in.(5 cm) apart. This allows many substances to be tested at the same time.  Prick the skin under each drop with a needle. The needle passes through the drop and allows some of the allergen to penetrate your skin. For the intradermal test, a needle is used to inject the allergen solution deeper into the skin. See an illustration of a skin prick allergy test .  Check the skin after 12 to 15 minutes for red, raised itchy areas called wheals. If a wheal forms, it means you are allergic to that allergen (this is called a positive reaction).An alternative skin prick method uses a device with 5 to 10 points (heads), which are dipped into bottles that contain theallergen extract. This device is pressed against the skin of the forearm or back so that all heads are pressed into theskin at the same time.If the skin prick test is negative, you may have an intradermal skin test. The skin prick test is usually done first, though,because the intradermal test has a greater risk of causing a severe allergic reaction.The skin prick test and the intradermal test usually take less than an hour.A skin patch test also uses small doses of the suspected allergen. For this test:  Doses of allergens are placed on patches that look like adhesive bandages.  The patches are then placed on the skin (usually on your back). This usually takes about 40 minutes, depending on how many patches are applied. See an illustration of a skin patch allergy test .  You will wear the patches for 24 to 72 hours. Do not take a bath or shower or do any activities that could make you sweat excessively while you are wearing the patches. This could loosen the patches and cause them to fall off.  The patches will be removed by your health professional, and your skin will be checked for signs of an allergic reaction.
    • Blood testThe health professional drawing your blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.The blood sample will be placed on specially treated paper and sent to a lab to determine whether antibodies to any ofthe allergens being tested are present. If specific antibodies are detected, it may mean you are allergic to a certainallergen.How It FeelsSkin testsWith the skin prick test and the intradermal skin test, you may feel a slight pricking sensation when the skin beneatheach sample is pricked or when the needle penetrates your skin.If you have an allergic reaction from any of the skin tests, you may have some itching, tenderness, and swelling wherethe allergen solutions were placed on the skin. After the testing is done, cool cloths or a nonprescription steroid creamcan be used to relieve the itching and swelling.If you are having a skin patch test and you have severe itching or pain under any of the patches, remove the patchesand call your health professional.Blood testYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain orhave only minor discomfort once the needle is positioned in the vein.RisksSkin testsThe major risk with the skin prick test or the intradermal skin test is a severe allergic reaction called anaphylaxis.Symptoms of a severe allergic reaction include itching, wheezing, swelling of the face or entire body, difficulty breathing,and low blood pressure that can lead to shock. An anaphylactic reaction can be life-threatening and is a medicalemergency. Emergency care is always needed for an anaphylactic reaction. However, severe allergic reaction is rare,especially with the skin prick test.If you are having a skin patch test and you have severe itching or pain under any of the patches, remove the patchesand call your health professional.Blood testThere is very little risk of a problem from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin) and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.
    • ResultsAllergy testing involves having a skin or blood test to determine what substance, or allergen, may trigger an allergicresponse in a person.Skin testsSkin tests work by exposing a person to suspected allergens and seeing if a reaction occurs. The results of the skintests will be available immediately after testing is done. Allergy skin tests Normal No raised red areas (called wheals) are created by the allergen. (negative): A wheal created by the allergen is at least 1/8 inch (3 mm) larger than the reaction to the negative Abnormal control. The larger the wheal, the more certain it is that the person is allergic to that specific allergen. (positive): See an illustration of a positive patch test reaction .Blood testsAllergy blood tests look for substances in the blood called antibodies. Results of allergy blood tests are usually availablein about 7 days. Allergy blood tests Normal The levels of immunoglobulin E (IgE), a type of antibody, are the same as in a person who does (negative): not have allergies. Abnormal The levels of immunoglobulin E (IgE) antibodies for a particular allergen or group of allergens are (positive): 4 times the normal level.What Affects the TestReasons you may not be able to have the test or why the results may not be helpful include:  Medications, such as antihistamines or tricyclic antidepressants.  Having a radioactive scan (such as a bone or thyroid scan) within 1 week before radioallergosorbent testing (RAST).  Parasitic infections.  Alcohol and beverages that contain caffeine.  Exercise that causes excessive sweating.  Getting a skin patch wet.What To Think About  You may not need allergy testing if you have mild allergies that are easily controlled with medication or lifestyle changes.  Skin tests: o Are the easiest and least expensive method for identifying allergies in most people. o Are more reliable than blood tests for identifying common inhaled (airborne) allergies, such as trees, pollens, dust, mold, and pet dander. o Cannot determine whether a person is reacting to a certain food. Further testing (such as an elimination diet) may be needed to identify this. o Can be unpleasant for children and their parents. o May take as long as 3 to 4 hours.  Allergy blood tests: o Are less sensitive than skin tests. Therefore, it is possible for people to have a positive reaction to a skin test but have a negative reaction to a blood test. o Are not affected by antihistamines or tricyclic antidepressants, so people do not need to stop taking these medications while being tested. o May be a good choice if you have very sensitive skin or a skin problem, such as eczema, that would make it hard to see whether you have a reaction to a skin test. o Will not cause an allergic reaction. They may be used if you have had a serious allergic reaction in the past.
    • o Are more expensive than skin tests.  You may need to be tested for a latex allergy before having a major surgery if you have had frequent exposure to latex. Allergy blood tests are used for this. If you have a latex allergy, latex products should not be used during your surgery or recovery.  Other blood tests, such as fluoro-allergosorbent testing (FAST), multiple antigen simultaneous testing (MAST), and enzyme-linked immunosorbent assay (ELISA), are sometimes used to check for allergens.ReferencesOther Works Consulted  Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.  Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.  Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.  Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.
    • Antisperm Antibody Test Test OverviewAn antisperm antibody test detects antibodies against a mans sperm in blood, vaginal secretions, and semen. Theantibody test combines a sample of sperm with particles that bind only with antibody-affected sperm.Semen can trigger an immune response in either the mans or womans body, and the resulting antibodies can disableor kill sperm. If a high number of sperm antibodies come into contact with a mans sperm, the couples chance ofconceiving may be impaired. This is called immunologic infertility.A man can produce sperm antibodies when his sperm are exposed to his immune system (the testicles normally keepsperm isolated from the rest of the body and its immune system). This can happen after damage to the testicles,surgical procedures (such as biopsy or vasectomy), and prostate gland infection.A woman can develop an allergic reaction to her partners semen and produce sperm antibodies. This kind of immunereaction is not fully understood but may affect fertility.Why It Is DoneThe antisperm antibody test may be done if:  Prior testing has not determined a cause for infertility (unexplained infertility). The usefulness of the antisperm antibody test is controversial because the results are unlikely to change any treatment your health professional recommends.  Abnormal results from the postcoital test (such as no sperm or dead or impaired sperm) require further investigation. For more information, see the medical test Postcoital Test.How To PrepareTalk to your health professional about any concerns you have regarding the need for the test, its risks, how it will bedone, or what the results will indicate. To help you understand the importance of this test, fill out the medical testinformation form (What is a PDF document?).Blood and vaginal secretions sampleSince the blood and vaginal secretions samples must be obtained during ovulation, you will need to monitor your basalbody temperature and cervical mucous (as well as your urine luteinizing hormone [LH], if you choose); follow yourhealth professionals guidelines. If you choose to check your LH level, do the urine test in the mid- to late-morning, anddo not drink any liquids that morning until you have completed the test. If your monitoring or test indicates that you areovulating, make an appointment to have the samples taken the following day.Semen sampleAfter the blood and vaginal secretions samples have been obtained from the woman, the semen sample can becollected from the man. The sample must be collected after refraining from sexual intercourse for at least 48 hours butno longer than 5 days.How It Is DoneFor an antisperm antibody test, blood and vaginal secretion samples are obtained from the woman when she isovulating. After the samples are obtained from the woman, a semen sample is obtained from the man.Blood sample from the woman
    • The health professional drawing blood will wrap an elastic band around your upper arm to temporarily stop the flow ofblood through the veins in your arm. This makes it easier to put a needle into a vein properly because the veins belowthe band get larger and do not collapse easily.The needle site is cleaned with alcohol and the needle is inserted. If the needle does not get placed correctly or if thevein cannot supply enough blood, more than one needle stick may be needed.When the needle is properly placed in the vein, a collection tube will be attached to the needle and blood will flow into it.Sometimes more than one tube of blood is collected.When enough blood has been collected, the band around your arm will be removed. A gauze pad or cotton ball isplaced over the puncture site as the needle is withdrawn. Pressure is applied to the puncture site for several minutesand then a small bandage is often placed over it.Vaginal secretions sampleA sample of cervical mucus is collected from the woman using a pelvic examination. For more information, see themedical test Pelvic Examination.Semen sampleA semen sample is collected by masturbation. You should urinate and then wash and rinse your hands and penis beforecollecting the semen in a sterile container. You cannot use lubricants or condoms when collecting the sample. If you areallowed to collect the sample at home, it must be delivered to the laboratory within 30 minutes. The sample cannot becollected by interrupting sexual intercourse (coitus interruptus).How It FeelsBlood testYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people feel no pain or onlyminor discomfort once the needle is positioned in the vein. The amount of pain you have depends on the skill of thehealth professional drawing the blood, the condition of your veins, and your sensitivity to pain.Vaginal secretions sampleA pelvic examination to collect a sample of vaginal secretions is more comfortable if you and the health professional arerelaxed during the procedure. Breathing deeply and having a light conversation with your health professional may helpyou relax. Holding your breath or tensing your muscles will increase your discomfort.When the speculum is inserted for the internal examination, you may feel some pressure or mild discomfort. Try to relaxyour legs and hips as much as you can. If a metal speculum is used, the metal may feel cold and hard.Semen sampleProducing a semen sample does not cause any discomfort. However, you may feel embarrassed about the methodused to collect it. If masturbation is against your religious beliefs, discuss alternate methods of collection with yourdoctor.RisksBlood sampleThere is very little risk of complications from having blood drawn from a vein. You may develop a small bruise at thepuncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle iswithdrawn.Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usuallytreated by applying a warm compress several times daily.
    • Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell the health professional before your blood is drawn.Vaginal secretions sampleThere are no risks associated with a pelvic examination to collect a sample of vaginal secretions.Semen sampleThere are no risks associated with collecting a semen sample.ResultsAn antisperm antibody test detects antibodies against a mans sperm in blood, vaginal secretions, and semen. Thehigher the level of antibody-affected sperm identified in the semen, the lower the chance of conception.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  Using douches or vaginal creams or preparations within 24 hours before a pelvic examination to collect vaginal secretions.  Collecting a semen sample within 48 hours following sexual intercourse or longer than 5 days following sexual intercourse.  Collecting blood and vaginal secretions samples when a woman is not ovulating.What To Think About  Sperm antibodies found in you or your partner may have no bearing on your fertility.  The usefulness of antibody testing is controversial because many health professionals will recommend 1 the same infertility treatment regardless of whether antibodies are present.  For more information on infertility testing, see the medical test Infertility Testing.ReferencesCitations 1. Speroff L, et al. (1999). Female infertility. In Clinical Gynecologic Endocrinology and Infertility, 6th ed., pp. 1013–1042. Philadelphia: Lippincott Williams and Wilkins.
    • Antibody Tests Test OverviewAntibody tests are done to find antibodies against red blood cells. Antibodies are proteins produced by the immunesystem. Normally, antibodies bind to foreign substances, such as bacteria and viruses, causing them to be destroyed.Certain conditions can result in the production of antibodies against red blood cells.Transfusion reactionHuman blood is typed by the presence of certain markers (called antigens) on the surface of red blood cells . If youreceive a blood transfusion, the transfused blood must be compatible; that is, it must contain antigens that are the sameas the antigens on your own red blood cells. If you receive a transfusion of blood containing antigens different fromyours (incompatible blood), your immune system destroys the transfused blood cells. This destruction is called atransfusion reaction and can cause serious illness or even death.Rh sensitizationRh is an antigen. The full name for this antigen is Rhesus factor.If a pregnant woman with Rh-negative blood has a baby (fetus) with Rh-positive blood, Rh sensitization is a risk. Thisoccurs when the babys blood mixes with the mothers blood during delivery, causing the mothers immune system toproduce antibodies against the babys red blood cells in future pregnancies. This antibody response is called Rhsensitization and, depending on when it occurs, can destroy the babys red blood cells. Once sensitization occurs, thebaby can develop mild to severe problems (called Rh disease, hemolytic disease of the newborn, or erythroblastosisfetalis). If untreated, complications from sensitization can, in rare cases, lead to the death of an Rh-positive baby.A woman with Rh-negative blood can receive a vaccine called Rh immune globulin (such as RhoGAM) that almostalways prevents sensitization from occurring. Problems arising from Rh sensitization have become very rare since theRh immune globulin vaccine was developed.Autoimmune hemolytic anemiaA form of hemolytic anemia called autoimmune hemolytic anemia is a rare disease that causes antibodies to beproduced against a persons own red blood cells.Two blood tests detect the presence of antibodies against red blood cells: the indirect Coombs test and the directCoombs test. The indirect Coombs test detects antibodies that could bind to certain red blood cells, leading toproblems if blood mixing occurs. The direct Coombs test detects antibodies that are already attached to red blood cells.Why It Is DoneDirect Coombs testThe direct Coombs test checks for antibodies attached to your own red blood cells. The antibodies may be those yourbody produced because of disease or those you received in a blood transfusion. The rare condition of having antibodiesagainst your own red blood cells is called autoimmune hemolytic anemia.The direct Coombs test also may be done on a newborn baby whose mother has Rh-negative blood. The test resultsdetermine whether the mother has formed harmful antibodies and transferred them through the placenta to her fetus.Indirect Coombs test
    • The indirect Coombs test checks for antibodies against red blood cells circulating in your blood but not attached to yourred blood cells. The indirect Coombs test is commonly done to detect antibodies in a recipients or donors blood prior toa transfusion.A slightly different form of this test, the Rh antibody titer, is done early in pregnancy to determine a womans blood type.A woman with Rh-negative blood can produce antibodies against her babys blood if the baby has Rh-positive blood.This condition is called Rh sensitization and does not occur unless the babys blood mixes with the womans bloodusually at delivery. The Rh antibody titer test detects the presence of anti-Rh antibodies in the pregnant womans blood.Pregnant women with Rh-negative blood often have this test done early in pregnancy. Repeated testing throughout thepregnancy may be needed so steps can be taken to protect the baby.How To PrepareNo special preparation is needed before having this test.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. If the needle is not placed correctly or if the vein collapses, more than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksRisks of a blood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsAntibody tests are done to detect antibodies against red blood cells.NormalNo antibodies are detected. This is called a negative test result.  Direct Coombs test. A negative test result means that your blood contains no antibodies that are already attached to your red blood cells.  Indirect Coombs test. A negative test result means that your blood is compatible with the blood you are to receive by transfusion. A negative indirect Coombs test for Rh factor (Rh antibody titer) in a
    • pregnant woman means that she has not developed antibodies against the blood of her baby if her baby has Rh-positive blood. This means that Rh sensitization has not occurred.Abnormal test results  Direct Coombs test. The detection of antibodies attached to your red blood cells indicates that your blood has antibodies against red blood cells in your bloodstream. This is called a positive test result. This can be caused by a transfusion of incompatible blood or may be associated with conditions such as hemolytic anemia, systemic lupus erythematosus (SLE), hemolytic disease of the newborn (HDN), lymphoma, mycoplasma infection, advanced stage cancer, or infectious mononucleosis.  Indirect Coombs test. A positive test result, or the detection of antibodies against red blood cells from a donor, may indicate that your blood is incompatible with the donors blood and you cannot receive blood from that person. If the Rh antibody titer test is positive in a woman who is pregnant or is planning to become pregnant, it means that her immune system has formed antibodies against Rh-positive blood (Rh sensitization). She will be tested to determine the blood type of her baby. If the baby has Rh-positive blood, close monitoring throughout the pregnancy is needed to prevent serious damage to the babys red blood cells caused by the mothers immune system. If sensitization has not occurred, it can usually be prevented by an injection of the Rh immune globulin vaccine.What Affects the TestFactors that can interfere with your test and the accuracy of the results include:  A previous blood transfusion, a dextran injection, or a recent X-ray that required the use of contrast material given intravenously (IV).  Being pregnant within the past 3 months.  Medications. These include penicillin, ampicillin, cephalosporins, sulfa medications, tuberculosis medications, insulin, quinidine, levodopa, methyldopa, captopril, chlorpromazine, indomethacin, procainamide, tetracyclines, and phenytoin (Dilantin).What To Think AboutA newborn baby (whose mother has Rh-negative blood) may have a direct Coombs test to determine the presence ofantibodies against the babys red blood cells. The test results indicate whether the mother has formed harmfulantibodies and transferred them through the placenta to her baby. If the test is positive, the baby may need atransfusion with compatible blood to prevent anemia.
    • Immunoglobulins Test OverviewAn immunoglobulins test is done to measure the level of immunoglobulins, also known as antibodies, in your blood.Antibodies are substances produced by the bodys immune system in response to bacteria, viruses, or other foreignsubstances, such as fungus, animal dander, or cancer cells. Antibodies attach to the foreign substances, causing themto be destroyed by other immune system cells. See an illustration of the immune system .Antibodies are usually specific to each type of foreign substance. For example, antibodies produced in response to atuberculosis infection attach only to tuberculosis bacteria. Antibodies also play a role in allergic reactions. Occasionallyantibodies may be produced against a persons own tissues. This is called an autoimmune disease.A person whose immune system produces low levels of antibodies may be at an increased risk of developing repeatedinfections. A person may be born with an immune system that produces low levels of antibodies, or the immune systemmay produce low levels of antibodies in response to certain diseases, such as cancer.The five major types of antibodies are:  IgA. IgA antibodies are found mainly in areas of the body such the nose, breathing passages, digestive tract, ears, eyes, and vagina. IgA antibodies protect body surfaces that are exposed to the outside from foreign organisms and substances. This type of antibody is also found in saliva and tears. About 10% to 15% of the antibodies usually present in the body are IgA antibodies. A small percentage of people do not make IgA antibodies.  IgG. IgG antibodies are found in all body fluids. They are the smallest but most abundant of the antibodies, normally comprising about 75% to 80% of all the antibodies in the body. IgG antibodies are considered the most important antibodies for fighting bacterial and viral infections. IgG antibodies are the only type of antibody that can cross the placenta. Therefore, the IgG antibodies of a pregnant woman can also help protect her baby (fetus).  IgM. IgM antibodies are the largest type of antibody. They are found in blood and lymph fluid and are the first type of antibody produced in response to an infection. They also cause other immune system cells to produce compounds that can destroy invading cells. IgM antibodies normally comprise about 5% to 10% of all the antibodies in the body.  IgD. IgD antibodies are found in small amounts in the tissues that line the abdominal or chest cavity of the body. The function of IgD antibodies is not well-understood. They appear to play a role in allergic reactions to some substances such as milk, some medications, and some poisons.  IgE. IgE antibodies are found in the lungs, skin, and mucous membranes. They cause the body to react against foreign substances such as pollen, fungus spores, and animal dander. IgE antibody levels are often high in people with allergies.The levels of each type of antibody can give your health professional information about the cause of a medical problem.Why It Is DoneA test for immunoglobulins (antibodies) in the blood is done to:  Diagnose certain autoimmune diseases or allergies.  Diagnose certain types of cancer (such as multiple myeloma or macroglobulinemia) that affect immunoglobulin levels in distinctive ways.  Determine whether recurring infections are due to a low level of immunoglobulins (especially IgG).  Monitor treatment for certain types of cancer affecting the bone marrow.  Monitor treatment for Helicobacter pylori bacteria.  Monitor responses to immunizations to determine whether immunity is present.
    • This test is often done when the results of a protein electrophoresis or total blood protein test are abnormal.How To PrepareThere is no special preparation for this test.How It Is DoneThe health professional drawing blood will:  Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.  Clean the needle site with alcohol.  Put the needle into the vein. More than one needle stick may be needed.  Attach a tube to the needle to fill it with blood.  Remove the band from your arm when enough blood is collected.  Apply a gauze pad or cotton ball over the needle site as the needle is removed.  Apply pressure to the site and then a bandage.How It FeelsYou may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes throughthe skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain(or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on theskill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.RisksBlood testThere is very little risk of complications from having blood drawn from a vein.  You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.  Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.  Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell your health professional before your blood is drawn.ResultsAn immunoglobulins test is done to measure the level of immunoglobulins, also known as antibodies, in your blood.NormalNormal values may vary from lab to lab. The results listed below are normal values