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Value of urinalysis in clinical medicine   copy Value of urinalysis in clinical medicine copy Presentation Transcript

  • Value Of Urinalysis In Clinical Medicine Dr./ Sahar Hamdy Medical consultant El-Mataria Teaching Hospital, Cairo
  • Introduction Urine formed in the kidneys, is a product of ultrafiltration of plasma by the renal glomeruli.
  • Formation of Urine Three processes of urine formation: glomerular filtration tubular reabsorption tubular secretion The nephron: allows for • reabsorption of water and electrolytes plays a vital role in • maintaining normal fluid balance
  • Physical Composition and Chemical Properties Urine 95% water 5% waste products Other dissolved chemicals Urea, uric acid, ammonia, calcium, creatine, sodium, chlorid e, potassium, sulfates, ph osphates, bicarbonates, h ydrogen ions, urochrome, urobilino gen
  • Obtaining Specimens General guidelines:  Use the type of specimen container indicated by the lab  Label the specimen container before giving it to patient  Explain the procedure to patient  Wash your hands before and after procedure  Complete all necessary paperwork
  • Specimens Types It Varies in method used and in time frame in which to collect specimen Types of specimens: Random  First morning  Clean catch midstream  Timed  24 hour 
  • Specimens Types (cont.)  Random – most common, taken anytime of day  First morning – has a greater concentration of substances, taken in morning  Clean catch midstream – genitalia is cleaned, urine is tested for microorganisms or presence of infection  Timed – specific time of day, always discard first specimen before timing  24 hour – used for quantitative and qualitative analysis of substances
  • Urinalysis Evaluation of urine to obtain information about body health and disease Four types of testing:  Physical  Chemical  Microscopic  Culture and sensitivity( beyond the scope of lecture)
  • Preservation and Storage Changes that affect the chemical or microscopic properties of urine occur if urine is kept at room temperature for more than 1 hour Refrigeration – most common method for storing and preserving urine It prevents bacterial growth for 24 hours. After 24 hours use chemical preservation
  • Normal Values of Urine  Normal values of various elements have been established  A routine vol. of 12 mL urine is analysed  Average adult urine output is 1250 mL/24 hours(>1mL/Kg/hour)
  • I- Physical Examination of Urine Visual examination of physical characteristics 1. 2. 3. 4. Volume Color and turbidity Odor Specific gravity/ Osmolality
  • Urinary volume Normal = 600-1550 mL/d Polyuria- > 2000mL Oliguria-< 400 mL Anuria-complete cessation of urine(< 200 mL) • Nocturia-excretion of urine by a adult of > 500 ml with a specific gravity of < 1.018 at night (c.c. of chronic GN) • • • •
  • Common Causes of polyuria       Diabetes mellitus Diabetes insipidus Polycystic kidney Chronic renal failure Diuretics Intravenous saline/glucose
  • Common Causes of Oliguria Acute renal failure: Pre-renal, renal and post-renal Hypovolemic: Dehydration / vomiting, diarrhea, excessive sweating Renal ischemia Acute tubular necrosis Obstructive Uropathy
  • Urinary Color And Its Clinical Significance  Normally urine is amber yellow and clear  Colourless: D.I., D.M., diuretics,..  Deep yellow: Conj. Bilirubin, phenacetin, riboflavin, mepacrine,..  Foamy: proteinuria  Milky: Pus, chyluria, spermatozoa, urate crystals(acidic urine), insoluble phosphates(alkaline urine),..  Orange: Fever, excessive sweating, metronidazole, aniline dyes(sweets), anthroquinones(laxatives), rifampicin,..  Red: Beeturia(anthrocyaninuria), porphyrins, hematuria, hemoglobi nuria, myoglobinuria, phenindione, phenolphthalein,..  Brown: Porphyria, alkaptonuria, L-dopa,..  Green: Pseudomonas, methylene blue, phenol, lysol,..
  • Urine Appearance Turbidity means:  Cellular elements,  Bacteria(which clear by centrifugation), and  Crystals(which clear by addition of acids or bases)… It’s the microscopic examination which will determine which type…
  • Urine Odour Normal: Urinefrous(aromatic volatile acids) • Sweety: Glucose • Fruity: Ketones • Foul, offensive: old specimen, pus
  • Urine Sp. Gr. / Osmolality • Specific Gravity depends on the concentration of various solutes in the urine. • N.Sp.Gr. = 1.016 – 1.022 • Hyperosthenuria: Dehydr., D.M.,.. • Hyposthenuria: Polyuria(except diabetes) • Isosthenuria: Fixed at 1.010 in CRF ////////////////////////////////////////////// There is a linear relationship between Sp. Gr. & Osmolality; ; ; Except in Glycosuria, or Excretion of contrast ----- In this case, the Sp. Gr. Will be > Osmolality
  • Measurement of Specific Gravity It’s measured by:  -urinometer  -refractometer  -dipsticks
  • Urinometer Method for use:  Take 2/3 of urinometer container with urine  Allow the urinometer to float into the urine  Read the graduation at the lowest level of urinary meniscus *Correction of temperature & albumin is a must.* Urinometer is calibrated at 15 or 200c So for every 3oc increase/decrease add/subtract 0.001 For 1gm/dl of albumin add 0.001
  • Apply Your Knowledge What is the specific gravity shown on this refractometer screen? 23
  • Apply Your Knowledge Answer What is the specific gravity shown on this refractometer screen? The specific gravity shown here is 1.030 24
  • Urinary Dipsticks
  • Dipsticks Use The main advantage of dipsticks is that they are 1. convenient, 2. easy to interpret, 3. and cost-effective • The main disadvantage is that 1.Not very accurate (the test is time-sensitive). 2. It is a qualitative and not a quantitative test (no precise information about the severity of the abnormality) .
  • II- Chemical Examination of Urine Usually done with reagent strips or tablets Used to determine body processes such as CHO metabolism, liver or kidney function or acid-base balance. Used to determine presence of drug, toxic environmental substances or infections
  • Chemicals In Urine
  • 1- Urinary pH/ reaction Reaction reflects ability of kidney to maintain normal hydrogen ion concentration in plasma & ECF Normal= 4.6-8 Tested by :- 1.litmus paper 2. pH paper 3. dipsticks Other Tests:  Titrable acidity  Blood gases
  • Significance Of Urinary pH reaction
  • • Buffers from the protein area of the strip (pH 3.0) spill over to the pH area of the strip and make the pH of the sample appear more acidic than it really is Dipstick for pH Limitations: • Interference: Bacterial overgrowth • Run-Over Effect: Protein pad effect on PH pad
  • 2- Urinary Glucose detection Detection of reducing sugars by: Benedict’s Test  Urinary dipsticks  Benedict: Semi-quantitative) Principle-Benedict’s reagent contains cuso4.In the presence of • reducing sugars cupric ions are converted to cuprous oxide which is hastened by heating, to give the color. Method- take 5ml of benedict’s reagent in a test tube, add 8drops of • urine. Boil the mixture.  Blue-green = negative  Yellow-green = +(<0.5%)  Greenish yellow = ++(0.5-1%)  Yellow = +++(1-2%)  Brick red = ++++(>2%) N.B: Renal threshold must be passed in order for glucose to spill into urine
  • Dipsticks for Glucose However, Benedict detects all reducing substances like glucose, fructose, & other reducing sustances such as: Sugar Disease Galactose Galactosemia Lactose Lactase def. or intolerance Fructose Fructose intolerance Pentose Essential pentosuria Maltose Non-pathogenic N.B: Sucrose is not a reducing substance To confirm it is glucose, dipsticks can be used (glucose oxidase)
  • Causes of glycosuria Glycosuria with hyperglycaemia• Diabetes, • Acromegaly, • Cushing’s disease, Hyperthyroidis m, • Drugs like corticosteroids Glycosuria without hyperglycaemia• Renal tubular dysfunction(ex. Fanconi syndrome; also with: a.a.uria & po4 uria) • Renal Glycosuria • TTT with SGLT(sodium glucose transport inhibitors used to treat DM)
  • 3- Urinary ketone detection There are 3 types of ketone bodies:  Acetone  Acetoacetate  Beta-hydroxy-butyrate Detection of ketones by:  Rothera’s Test  Dipsticks • Rothera’s t. principle:Acetone & acetoacetic acid react with sodium nitroprusside in the presence of alkali to produce purple colour. • Method- take 5ml of urine in a test tube & saturate it with ammonium sulphate. Then add one crystal of sodium nitroprusside. Then gently add 0.5ml of liquor ammonia along the sides of the test tube. • Change in colour indicates a positive result
  • Dipsticks For Ketones Significance: Diabetes Starvation Severe vomiting/diarrhea High fever Limitations:  Measure only acetoacetate and not other ketones >>>Cannot detect alcoholic KA(with ↑BHB >AA)  Reagents can undergo degradation with exposure to moist of air
  • 4- Urinary protein detection --Normally, up to 150 mg total proteins may be found in urine per 24 hours --More than 300 mg per 24 hours is termed “ Frank Proteinuria “ N.B Test-thermal method:water-bath) Proteins has an unusual and peculiar property of precipitation at 400 -600c & then dissolving when urine is brought to boiling at 1000c & then reappearing de novo on cooling of sample. Protein Max. (mg/day) % of Total Albumin 60 40 TammHorsefall 60 40 Igs 24 12 Secretory 6 IgA 3 Others 5 10
  • Tests for proteins Test – heat & acetic acid test Principle-proteins are denatured & coagulated on heating to give white cloud precipitate. Method-take 2/3 of test tube with urine, heat only the upper part keeping lower part as control. Presence of phosphates, carbonates, proteins gives a white cloud formation. Add acetic acid 1-2 drops, if the cloud persists it indicates it is protein(acetic acid dissolves the carbonates/phosphates) Other Tests: -Sulphosalicylic acid SSA turbidity test -Dipsticks -Esbach-albuminometer- for quantitative estimation of proteins -Urine protein electrophoresis(UPEP)
  • Albumin Excretion: Alternative Methods for expressing the normal range Sample Normal Value  24-h urine collection < 30 mg / 24 hrs  Timed sample from ambulant pt. < 20 micro-g / min  Timed sample for recumbent pt.(or over-night sample) < 10 micro-g / min  Albumin / creatinine ratio on a random urine sample < 2.5 mg / mmol in male) < 3.5 mg / mmol (in female)
  • Dipsticks for proteins Limitations: Interference: Highly alkaline urine -Almost all dipsticks detect proteins if present in an amount more than 300 mg / 24 Hs -They cannot detect micro-albuminuria (30150 mg) alb./24-h urinary sample >>>>> Esbach –albuminometer can be used … Bences- Jones proteins are light chain globulins present in multiple myeloma, macroglobulinemias and lymphomas They are detected by: UPEP N.B.: Usually +1 ptn. correlates with 30 mg alb. And +3 ptn. Correlates with > 500 mg alb.
  • Importance of micro-albuminuria  It is an early indicator of subclinical nephropathy either due to on intrinsic kidney disease or due to a cardiovascular disease..  It may be an important prognostic marker..?  It is considered as a routine check-up in all cases of diabetes mellitus or in hypertension (every 6 months)..  Serial rise in micro-albuminuria during the first 48 hours after admission to an intensive care unit can predict elevated risk for acute respiratory failure , multiple organ failure , and overall /CV mortality (as a bad prognostic criterion.. )
  • Causes Of Proteinuria Functional • Pregnancy • Orthostatic(<1 gm/24h) • Severe Ms.exertion Prerenal • Fever • Hypoxia • HTN • Renal vein thrombosis • Severe exfoliative skin dis.(eg psoriasis) Renal Postrenal • GN • NS • Diabetes • SLE • Amyloidosis • UTI • Tumours • Cystitis/Ureth ritis • Prostatitis • Obstructive uropathy • Contaminated vaginal secretions
  • 5-Urine blood detection Test- BENZIDINE TEST Principle-The peroxidase activity of hemoglobin decomposes hydrogen peroxide releasing nascent oxygen which in turn oxidizes benzidine to give blue color. Method- mix 2ml of benzidine solution with 2ml of hydrogen peroxide in a test tube. Take 2ml of urine & add 2ml of above mixture. A blue color indicates + reaction.
  • Significance - Hematuria: Nephritis, trauma,.. - Hemoglobinuria: Hemolysis (decr.haptoglobin),.. - Myoglobinuria: Rhabdomyolysis (N.haptoglobin),.. Limitations - Interference: reducing agents, microbial peroxidases - Cannot distinguish between the above disease processes Other Tests - Urine microscopic examination - Urine cytology
  • Causes of hematuria Pre renal- bleeding diathesis, hemoglobinopathies, malignant hypertension. Renal- Trauma, calculi, ac. & chr. glomerulonephritis, pyelonephritis, renal TB, renal tumours, Goodpasture syndrome and Henoch-shonlein purpura Post renal – severe UTI, calculi, trauma, tumors of urinary tract
  • The Urine Dipstick: Negative Trace (non-hemolyzed) Moderate (non-hemolyzed) Trace (hemolyzed) + (weak) ++ (moderate) +++ (strong) Blood Chemical Principle Lysing agent to lyse red blood cells Diisopropylbenzene dihydroperoxide + Tetramethylbenzidine Heme ------------> Colored Complex Read at 60 seconds RR: Negative Analytic Sensitivity: 10 RBCs
  • 6- Urine bilirubin or Urobilinogen Bilirubin Test- fouchet’s test. Causes • • Liver diseases, injury, hepatitis Obstruction to biliary tract Significance It correlates with D. serum bilirubin Limitations Urobilinogen Test- Ehrlich test Causes- hemolytic anemia's and hepatocellular jaundice Significance - High: increased hepatic processing of bilirubin - Low: bile obstruction - Interference: prolonged exposure of sample to light - Only measures direct bilirubin--will not pick up indirect bilirubin Limitations - Ictotest (more sensitive tablet version of same assay) Other Tests Other Tests - Interference: prolonged exposure of specimen to oxygen (urobilinogen --> urobilin) - Cannot detect low levels of urobilinogen - Serum total and direct bilirubin
  • Dipsticks for bilirubin and urobilinogen Bilirubin Urobilinogen
  • 7- Urinary detection of nitrites Significance:- Gram negative bacteriuria Limitations - Interference: bacterial overgrowth - Only able to detect bacteria that reduce nitrate to nitrite Other Tests - Correlate with leukocyte esterase and urine microscopic examination (bacteria) - Urine culture
  • The Urine Dipstick for nitrite: Chemical Principle Negative Positive Acidic Nitrite + p-arsenilic acid -------> Diazo compound Diazo compound + Tetrahydrobenzoquinolinol ----------> Colored Complex Read at 60 seconds RR: Negative
  • 8- Urinary detection of leucocyte esterase Significance - Pyuria - Acute inflammation - Renal calculus Limitations - Interference: oxidizing agents, menstrual contamination Other Tests - Urine microscopic examination (WBCs and bacteria) - Urine culture
  • The Urine Dipstick: Leukocyte Esterase Chemical Principle Derivatized pyrrole amino acid ester Negative Trace + (weak) Esterases ------------> 3-hydroxy-5-phenyl pyrrole 3-hydroxy-5-phenyl pyrrole + diazo salt -------------> Colored Complex ++ (moderate) +++ (strong) Read at 2 minutes RR: Negative Analytic Sensitivity: 3-5 WBCs
  • III- Microscopic Examination of Urine • Centrifuge the urine sample for a few minutes (10-20 fold conc.) • Discard the supernatant. • The solid part left in the bottom of the test tube (the urine sediment) is mixed with the remaining drop of urine in the test tube and one drop is analyzed under a microscope • FOV(field of view): What is seen through the ocular lens A normal urine contains few epithelial cells, occasional RBC’s, few crystals.
  • Types of microscopy: 1. Phase contrast 2. Polarized 3. Bight field with special staining N.B:Cells and casts begin to disintegrate in 1 - 3 hrs. at room temp( refrigeration for up to 48 hours is a must to limit cell loss). Presence of the following is considered “abnormal”: o Fungal hyphae or yeast, parasite, viral inclusions o Mononuclear cells(transplant rejection), eosinophils (all. Interstitial nephritis, vasculitis, prostatitis & atheroembolic dis.) o Sperms(post-vasectomy),starch, mucus, fibres o Pathological crystals (cystine, leucine, tyrosine) o Large number of uric acid or calcium oxalate crystals
  • Abnormal Microscopical Findings Per high power field(x40)  > 3 erythrocytes  > 5 leukocytes(glitter cells) Eosinophils: Giemsa or Hansel stain  > 2 renal tubular cells  > 1 bacteria  Mononuclear cells  Yeast  Trichomonas  Crystals Per low power field(x10)  > 3 hyaline casts  > 1 granular cast  > 10 squamous cells (contaminated specimen)  Any other cast (RBCs, WBCs)
  • RBCS appear dysmorphic(mickey-mouse RBCs) in glomerular bleeding; whilst derived from LUT, they look normal
  • Leptospira, athero-embolic dis, tubulo-interstitial nephritis, or sarcoidosis
  • Squamous cells Tubular Epithelial cells
  • Transitional Cells
  • Oval Fat Bodies
  • LE Cells
  • Bacteria
  • Yeasts
  • Cytomegalovirus
  • Crystals in urine Crystals are not a normal finding in a fresh urinary sample Crystals in acidic urine  Uric acid  Calcium oxalate  Cystine  Leucine  Tyrosine  Cholesterol  Bilirubin Crystals in alkaline urine  Amorphous phosphates  Triple phosphates (NH4 Mg PO4: Struvite)  NH4 bi-urate  Calcium carbonate Others Drug-induced (sulfonamide and radiocontrast)
  • Oxalate Crystals Bi-pyramidal or bi-concave ovals
  • Triple Phosphate Crystals
  • Urate Crystals Flat-square plates
  • Leucine crystals
  • Cystine Crystals Flat Hexagonal Plates
  • Ammonium bi-urate crystals
  • Cholesterol crystals
  • Urinary Casts  Urinary casts are cylindrical aggregations of particles that form in the distal nephron, dislodge, and pass into the urine.  In urinalysis they indicate kidney disease.  They form via precipitation of TammHorsfall mucoprotein which is secreted by renal tubule cells.  Cast formation is enhanced by: • PH of urine • Solute conc. • Presence of plasma proteins(albumin, globulin, hemoglo bin, myoglobin,..
  • Types of casts Acellular casts • • • • • • • Hyaline casts Granular casts Waxy casts Fatty casts Pigment casts Crystal casts Broad casts Cellular casts • Red cell casts • White cell casts • Epithelial cell cast
  • Casts and clinical significance Urinary Cast Clinical Significance RBCs Cast GN, tubular bleeding WBCs Cast • PN, or acute Allergic IN, ATN, sarcoidosis, SLE, Wegner’s • Ac. GN(post-strept), NS, atheroembolic disease,.. Hyaline Cast • Normal (Tamm-Horsfall glycoprotein) • Fever, exercise, dehydration, emotional stress,.. Tubular Cast • ATN, nephrotoxic injury(aminoglycosides and cisplastin), IN Granular Cast Non-Specific (can result either from breakdown of cellular cast or from aggregation of plasma proteins) indicate CKD Fatty Cast • NS, DM, ATN, SLE
  • Casts and clinical significance Urinary Cast Clinical Significance Broad Cast CRF (Formed in dilated remaining tubules showing compensatory hypertrophy) Pigment Cast (Formed by the adhesion of metabolic breakdown products or drug pigments) Hemolytic anemia, rhabdomyolysis, liver disease Epithelial Cast ATN, intoxication with mercury, salicylate or diethylene glycol Crystal Cast (Formed by incorporation of Heavy crystal load crystallised urinary solutes with hyaline casts) Prolonged stasis (CKD)
  • RBCS Cast
  • WBCs Cast
  • Hyaline Cast
  • Tubular Cast
  • Granular Cast
  • Fatty Cast
  • Waxy Cast
  • Cytological Examination Staining: o o o o o Papanicolaou stain Wright’s stain Hansel’s stain Immunoperoxidase sp. stain Immunofluorescence sp. stain
  • Cytology Normal Reactive
  • Transitional Cell Carcinoma Low Grade High Grade
  • Squamous Cell Carcinoma Prostatic Carcinoma
  • Common Microscopically Urinary Findings in various Diseases DISEASE FINDINGS 1- Acute glomerulonephritis Dysmorphic RBCs – RBCs and mixed cellular Casts 2- Chronic glomerulonephritis RBCs and broad waxy Casts 3- Acute pyelonephritis Bacteria – Leucocytes – Granular, leucocyte, waxy and renal tubular epithelial Casts 4- Nephrotic syndrome Oval fat bodies – Fatty casts – Waxy casts 5- Acute tubular necrosis Renal tubular epithelial cells – Pathological Casts 6- Eosinophilic cystitis No significant casts – Numerous eosinophils
  • Urinalysis Disease diagnosis AND Case study
  • Case 1 A 35-year old man undergoing routine pre employment drug screening. Glucose Negative Bilirubin Negative Ketones Negative S.G. 1.001 Blood Negative pH 5.5 Protein Negative Urobilinogen 0.2 mg/dL Nitrite Negative L.E. Negative Physical characteristics: Clear. . Microscopic: Not performed Drugs Identified: None Questions : - What is your differential diagnosis? - What would you do next to confirm your suspicion? - Would you order a microscopic analysis on this sample?
  • Answer 1 Diluted urine with a low Sp. Gr.>>>>> Request a morning urine sample>>>>> If persisting low Sp.Gr.>>>>> Possible diagnosis of diabetes insipidus
  • Case 2 A 42-year old woman presents with “dark urine” Glucose Negative Bilirubin +++ Ketones Negative S.G. 1.020 Blood Negative pH 5.5 Protein Negative Urobilinogen 0.2 mg/dL Nitrite Negative L.E. Negative Physical characteristics: Red-brown. Microscopic: Not performed. Questions - What is your differential diagnosis? - Could this be a case of hemolytic anemia? - How would you rule it out? - What tests would you order next? Why? - Would you order a microscopic analysis?
  • Answer 2 Possible gallbladder or hepatic disease. No hemolytic anemia. Perform Serum assessment for total and direct bilirubin Microscopic exam. is unlikely to provide additional information for diagnosis
  • Case 3 A 27-year old woman presents with severe abdominal pain. Glucose ++ Bilirubin Negative Ketones Trace S.G. Physical characteristics: clear-yellow. Microscopic: Not performed. 1.015 Blood Negative pH 6.0 Protein Negative Urobilinogen 1.0 mg/dL Nitrite Negative L.E. Negative Questions - What is the most likely diagnosis? - What do you make of the ketone result? - What do you expect to happen to the ketone measurement when treatment begins?
  • Answer 3 Diabetes May be associated with ketoacidosis Ketones should become negative after treatment
  • Case 4 8-year old boy presents with discolored urine Glucose Negative Bilirubin Negative Ketones Negative S.G. 1.015 Blood +++ pH 6.5 Protein + Urobilinogen 1.0 mg/dL Nitrite Negative L.E. Negative Physical characteristics: Red, turbid. Microscopic: erythrocytes = >100 per HPF (almost all dysmorphic) Red cell casts present. Questions: - What is the most likely diagnosis in this case? - Does the presence of red cell casts help you in any way? - If the erythrocytes were not dysmorphic would that change your diagnosis?
  • Answer 4 Glomerulonephritis RBC casts reveals renal cortex involvement
  • Case 5 Glucose Negative Bilirubin Negative Ketones Negative S.G. 1.010 Blood Negative pH 5.0 Protein + Urobilinogen 0.2 mg/dL Nitrite Negative L.E. Negative 22-year old man presenting for a routine physical required for admission to medical school Physical characteristics: Yellow Microscopic: Not performed Questions: - What is your differential diagnosis? - Would you order a microscopic analysis on this sample? - What would you do next to confirm the diagnosis?
  • Answer 5 “Functional” proteinuria ? Microscopic may reveal a few leukocytes Request protein concentration in 24 h urine