Lab test 1.pptx

Complete blood count
 The complete blood count (CBC) is a group of tests that
evaluate the cells that circulate in blood, including
 Red blood cells (RBCs).
 White blood cells (WBCs).
 Platelets (PLTs).

Complete blood count - WBC
 Description
 A WBC count, also called a leukocyte count, is part of a
complete blood count.
 It indicates the number of white cells in a microliter (μL, or
cubic millimeter) of whole blood.
 WBC counts may vary by as much as 2000 cells/μL (SI, 2 ×
109/L) on any given day due to strenuous exercise, stress, or
digestion.
 The WBC count may increase or decrease significantly in
certain diseases, but it’s diagnostically useful only when the
patient’s white cell differential and clinical status are
considered.

 Description
 The WBC differential is used to evaluate the distribution and
morphology of WBCs, providing more specific information about a
patient’s immune system than a WBC count alone.
 WBCs are classified as one of five major types of leukocytes—
neutrophils, eosinophils, basophils, lymphocytes, and monocytes—
and the percentage of each type is determined.
 The differential count is the percentage of each type of WBC in the
blood. The total number of each WBC type is obtained by
multiplying its percentage by the total WBC count.

Complete blood count-WBC
 Purpose
 To determine infection or inflammation
 To determine the need for further tests such as bone marrow
biopsy.
 To monitor response to chemotherapy or radiation therapy

 Purpose-WBC Differential
 To evaluate the body’s capacity to resist and overcome
infection.
 To detect and identify various types of leukemia.
 To determine the stage and severity of an infection.
 To detect allergic reactions and parasitic infections and
assess their severity
 To distinguish viral from bacterial infections

 Reference Values
 4000 to 10,000/μL (SI, 4 to 10 × 109/L).
 For an accurate diagnosis, differential test results always
must be interpreted in relation to the total white blood cell
(WBC) count.

 Abnormal Findings- Elevated Levels (leukocytosis)
 Infection
 Abscess
 Meningitis
 Appendicitis
 Tonsillitis
 Leukemia
 Tissue necrosis due to burns, myocardial
 infarction, or gangrene

 Elevated Levels- Nursing Implications
 Report any abnormal findings to the practitioner.
 Prepare to educate the patient about his diagnosis.
 Prepare the patient for further testing or surgery, as indicated.
 Provide emotional support to the patient and his family.
 Prepare to administer antimicrobial therapy as indicated.
 Institute isolation precautions as applicable

 Abnormal Findings- Decreased Levels (Leukopenia)
 Bone marrow depression
 Viral infections
 Ingestion of mercury or other heavy metals
 Exposure to benzene or arsenicals
 Influenza
 Typhoid fever
 Measles
 Infectious hepatitis

 Decreased Levels- Nursing Implications
 Report any abnormal findings to the practitioner.
 Prepare the patient for further testing or surgery, as indicated.
 Provide emotional support to the patient and his family.
 Prepare to administer antimicrobial therapy as indicated.
 Institute isolation precautions as applicable.

 Interfering Factors
 WBC Count
 Digestion, exercise, or stress
 Anticonvulsants, such as phenytoin derivatives; nonsteroidal
anti-inflammatory drugs such as indomethacin (Indocin); and
thyroid hormone antagonists (decrease).
 Precautions
 Completely fill the sample collection tube.
 Invert the sample gently several times to mix the sample and
the anticoagulant.

 Nursing Considerations- Before the Test
 Confirm the patient’s identity using two patient identifiers
according to facility policy.
 Explain to the patient that the WBC count and differential test
is used to detect an infection or inflammation (WBC count) or
evaluate the immune system (WBC differential).
 Advise the patient that a blood sample will be taken. Explain
that he may feel slight discomfort from the tourniquet and
needle puncture.

 Inform the patient that he doesn’t need to restrict food and
fluids but that he should avoid strenuous exercise for 24
hours before the test. Also tell him that he should avoid eating
a heavy meal before the test.
 If the patient is being treated for an infection, advise him that
this test will be repeated to monitor his progress.
 Notify the laboratory and physician of medications the patient
is taking that may affect test results; they may need to be
restricted

 After the Test
 If a hematoma develops at the venipuncture site, apply pressure. If
the hematoma is large, monitor pulses distal to the venipuncture
site.
 Instruct the patient that he may resume his usual diet, activity, and
medications discontinued before the test, as ordered.
 Be aware that a patient with severe leukopenia may have little or
no resistance to infection and requires infection control
precautions.

Complete blood count-RBC
 Description
 The RBC count, also called an erythrocyte count, is part of a
complete blood count.
 It’s used to detect the number of RBCs in a microliter (μL) or
cubic millimeter (mm3), of whole blood.
 The RBC count itself provides no qualitative information
regarding the size, shape, or concentration of Hb within the
corpuscles, but it may be used to calculate two erythrocyte
indices:
o Mean corpuscular volume (MCV)
o Mean corpuscular hemoglobin (MCH)

 Purpose
 To provide data for calculating mean corpuscular volume
(MCV) and mean corpuscular hemoglobin (MCH), which
reveal RBC size and hemoglobin (Hb) content.
 To support other hematologic tests for diagnosing anemia or
polycythemia.

 Adult females: 4 to 5 million red blood cells (RBCs)/μL (SI, 4
to 5 × 1012/L) of venous blood
 Adult males: 4.5 to 5.5 million RBCs/ μL (SI, 4.5 to 5.5 ×
1012/L) of venous blood

Abnormal Findings- Elevated Levels
 Absolute or relative polycythemia
 Nursing Implications
 Report abnormal findings to the practitioner.
 Prepare the patient for further testing as indicated.

Abnormal Findings - Decreased Levels
 Anemia
 Dilution caused by fluid overload
 Hemorrhage beyond 24 hours

 Hemoconcentration caused by prolonged tourniquet
constriction.
 Hemodilution caused by drawing the sample from the same
arm used for IV fluid infusion
 Diseases that cause RBCs to agglutinate or form rouleaux
(false decrease).
 Hemolysis resulting from rough handling of the sample or
drawing the blood through a small-gauge needle for
venipuncture.

 Precautions
 Handle the sample gently to prevent hemolysis.

 Nursing Considerations-Before the Test
 Explain to the patient that the RBC count is used to evaluate the
number of RBCs and to detect possible blood disorders.
 Advise the patient that a blood sample will be taken. Explain that
he may feel slight discomfort from the tourniquet and needle
puncture.
 Inform the patient that he doesn’t need to restrict food and fluids
for the test.

 During the Test
 Fill the collection tube completely.
 Invert the tube gently several times to mix the sample and the
anticoagulant.
 After the Test
 Apply pressure to the venipuncture site until bleeding stops.
 If a hematoma develops at the venipuncture site, apply direct
pressure.

Complete blood count- Platelet Count
 Description
 Platelets, or thrombocytes, are the smallest formed elements
in blood.
 They promote coagulation and the formation of a hemostatic
plug in vascular injury.
 Platelet count is one of the most important screening tests of
platelet function. Accurate counts are vital.

Complete blood count-Platelet Count
 Purpose
 To evaluate platelet production.
 To assess the effects of chemotherapy or radiation therapy on
platelet production.
 To diagnose and monitor severe thrombocytosis or
thrombocytopenia.

Platelet Count
 Adults: 140,000 to 400,000/μL (SI, 140 to 400 × 109/L)
 Critical Values
 Less than 50,000/μL (can cause spontaneous bleeding).
 Less than 5000/μL (possible fatal central nervous system
bleeding or massive GI hemorrhage)

Platelet Count
 Abnormal Findings- Elevated Levels (thrombocytosis)
 Hemorrhage.
 Infectious or inflammatory disorders
 Iron deficiency anemia
 Splenectomy or other recent surgery
 Pregnancy
 Chronic myelogenous leukemia

Platelet Count
 Elevated Levels- Nursing Implications
 Prepare the patient for additional testing, including a complete
blood count (CBC), bone marrow biopsy,
 Prepare to educate the patient about his diagnosis

Platelet Count
 Abnormal Findings-Decreased Levels
 Splenectomy.
 Leukemia.
 Disseminated infection
 Folic acid or vitamin B12 deficiency
 Pooling of platelets in an enlarged spleen.
 Increased platelet destruction caused by drugs or an immune
disorder
 Disseminated intravascular coagulation
 Mechanical injury to platelets

Platelet Count
 Nursing Implications -Decreased Levels
(thrombocytopenia)
 Prepare the patient for additional testing, including a CBC,
bone marrow biopsy, direct antiglobulin test (direct Coombs’
test), and serum protein electrophoresis.

Platelet Count
 Heparin (decrease)
 Furosemide (Lasix), penicillin, and tricyclic antidepressants
(possible decrease).
 Estrogens, oral contraceptives, excitement, high altitudes,
persistent cold temperatures, or strenuous exercise (increase)

Platelet Count
 Precautions
 To prevent hemolysis, avoid excessive probing at the
venipuncture site and handle the sample gently.
 Explain to the patient that the platelet count test is used to
determine if the patient’s blood clots normally.

Platelet Count
 Advise the patient that a blood sample will be taken. Explain
that he may feel slight discomfort from the needle puncture
and the tourniquet.
fluids for the test.
 Notify the laboratory and practitioner of medications the
patient is taking that may affect test results; they may need to
be restricted.

Platelet Count
 During the Test
 Completely fill the collection tube and invert it gently several
times to mix the sample and the anticoagulant thoroughly.
 After the Test
 Apply pressure to the venipuncture site until bleeding has
stopped.
 If a hematoma develops at the veni puncture site, apply direct
pressure. If the hematoma is large, monitor pulses distal to
the venipuncture site.
 Tell the patient that he may resume any medications that were
discontinued before the test as ordered.

Kidney function test (KFT)
 Serum creatinine test
 Blood urea nitrogen (BUN)

Blood Urea Nitrogen (BUN)
 Description
 The blood urea nitrogen (BUN) test is used to measure the
nitrogen fraction of urea, the chief end product of protein
metabolism.
 urea Formed in the liver from ammonia and excreted by the
kidneys, urea constitutes 40% to 50% of the blood’s
nonprotein nitrogen content.
 BUN level reflects protein intake and renal excretory capacity,
but it’s a less reliable indicator of uremia than the serum
creatinine level.

Blood Urea Nitrogen
 Purpose
 To evaluate kidney function and aid in the diagnosis of renal
disease
 To aid in the assessment of hydration.

Blood Urea Nitrogen
 8 to 20 mg/dL (SI, 2.9–7.5 mmol/L)
 Elderly patients: slightly higher, possibly to 69 mg/dL (SI, 25.8
mmol/L.
 Critical Values
 Less than 2 mg/dL (SI, 0.71 mmol/L)
 Greater than 80 mg/dL (SI, 2.85 mmol/L)

Blood Urea Nitrogen
 Abnormal Findings- Elevated Levels
 Renal disease (greater than 100 mg indicates serious
impairment of renal function).
 Reduced renal blood flow (due to dehydration, for example).
 Urinary tract obstruction.
 Increased protein catabolism (such as with burns).
 Prepare the patient for further testing.
 Explain the underlying problem associated with the elevated
level.

Blood Urea Nitrogen
 Decreased Levels
 Severe hepatic damage.
 Malnutrition
 Overhydration
 Prepare the patient for additional testing.
 Institute measures, as ordered, to correct nutritional and fluid
imbalances.

Blood Urea Nitrogen
 Chloramphenicol and tetracyclines (possible decrease)
 Overhydration and underhydration will affect BUN levels

Blood Urea Nitrogen
 Nursing Considerations-Before the Test
 Tell the patient that the BUN test is used to evaluate kidney
function.
fluids, but should limit his meat intake (protein intake affects
BUN levels).
 Explain to the patient that the test requires a blood sample
from a venipuncture. Advise him that he may experience
slight discomfort from the tourniquet and needle puncture.

Blood Urea Nitrogen
 After the Test
 Handle the sample gently and send it to the laboratory
immediately.
 Apply direct pressure to the venipuncture site until bleeding
stops.
 Inform the patient that he may resume medications that were
discontinued before the test, as ordered

Creatinine, Serum
 Description
 Serum creatinine levels provide a more sensitive measure of
renal damage than do blood urea nitrogen levels.
 Creatinine is a nonprotein end product of creatine metabolism
that appears in serum in amounts proportional to the body’s
muscle mass.
 Purpose
 To assess glomerular filtration
 To screen for renal damage

Creatinine, Serum
 Females: 0.6 to 0.9 mg/dL (SI, 53–97 μmol/L)
 Males: 0.8 to 1.2 mg/dL (SI, 62–115 μmol/L)
 Critical Values
 Less than 0.4 mg/dL (SI, 35 μmol/L) or
 More than 2.8 mg/dL (SI, 247 μmol/L)

Creatinine, Serum
 Plasma creatinine of 2 mg/dL indicates that renal disease has
seriously damaged 50% or more of the nephrons.
 Gigantism and acromegaly.
 Anticipate the need for additional testing.
 Prepare the patient for follow-up and treatment.
 Monitor fluid balance and intake and output.

Creatinine, Serum
 Abnormal Findings- Decreased Levels
 Liver disease
 Deficient levels of protein in the diet.
 Small build
 Loss of muscle mass
 Anticipate the need for additional testing.
 Prepare the patient for follow-up and treatment.
 Monitor fluid balance and intake and output.

Creatinine, Serum
 Ascorbic acid, barbiturates, and diuretics (possible increase)
 Exceptionally large muscle mass, such as is found in athletes
(possible increase despite normal renal function)

Creatinine, Serum
 Explain to the patient that the serum creatinine test is used to
evaluate kidney function.
 Tell the patient that the test requires a blood sample.
 Instruct the patient that he doesn’t need to restrict food and
fluids.
 Notify the laboratory and the practitioner of medications the
be restricted.

Creatinine, Serum
 Nursing Considerations- During the Test
 After the Test
 Send the sample to the laboratory immediately.
 Apply direct pressure to the venipuncture site until bleeding stops.
 Assess the venipuncture site for hematoma formation; if one
develops, apply pressure.
 Inform the patient that he may resume his usual medications that
were discontinued before the test, as ordered.

Liver Function Tests (LFT)
 Liver function tests are blood tests that measure different
enzymes, proteins, and other substances made by the liver.
The different substances are often tested at the same time on
a single blood sample, and may include the following:
 Albumin.
 Total protein.
 ALP (alkaline phosphatase), ALT (alanine transaminase), AST
(aspartate aminotransferase),
 Bilirubin, a waste product made by the liver.

Albumin
 Description
 The test measures the amount of albumin in serum.
 Albumin is the most abundant protein, composing almost 54%
of plasma proteins
 Purpose
 To help determine whether a patient has liver or kidney
disease
 To determine whether enough protein is being absorbed by
the body.

Albumin
 Adults: 3.5 to 4.8 g/dL (SI, 35–48 g/L)

Albumin
 Abnormal Findings- Elevated Levels (Hyperalbuminemia)
 Dehydration
 Severe vomiting
 Severe diarrhea
 Prepare to administer IV fluids to restore volume and
electrolytes.
 Educate the patient about his disease and treatment options.

Albumin
 Abnormal Findings- Decreased Levels (Hypoalbuminemia)
 Cirrhosis
 Acute liver failure
 Severe burns
 Severe malnutrition
 Ulcerative colitis
 Prepare to administer IV albumin.
 Educate the patient about his disease and treatment options.

Albumin
 Penicillin, sulfonamides, aspirin, and ascorbic acid (decrease)
 Heparin (increase)

Albumin
 Nursing Considerations - Before the Test
 Inform the patient that he doesn’t need to restrict fluids.
 Describe the venipuncture procedure to the patient.
 Explain that certain medications can increase albumin
measurements, including anabolic steroids, androgens,
growth hormones, and insulin.
 The patient may need to stop taking these drugs before the
test.

Albumin
 During the Test
 Perform a venipuncture, and collect 5 to 10 mL in a red-top
tube.
 After the Test
stops.
 Encourage the patient to eat a high protein diet, if not
contraindicated.

Bilirubin (Serum)
 Description
 The bilirubin test is used to measure serum levels of bilirubin,
the predominant pigment in bile.
 Bilirubin is the major product of hemoglobin catabolism.
 Serum bilirubin measurements are especially significant in
neonates because elevated unconjugated bilirubin can
accumulate in the brain, causing irreparable damage.

Bilirubin (Serum)
 Purpose
 To evaluate liver function.
 To aid in the differential diagnosis of jaundice and monitor its
progress.
 To help diagnose biliary obstruction and hemolytic anemia.

Bilirubin (Serum)
 Adults: indirect serum bilirubin levels, 0.1 to 1.0 mg/dL (SI,
1.7–17.1 μmol/L);
 Direct serum bilirubin levels, less than 0.5 mg/dL (SI, less
than 6.8 μmol/L)

Bilirubin (Serum)
 Hepatic damage or severe hemolytic anemia (elevated
indirect serum bilirubin).
 Hemolysis (elevated indirect and direct serum bilirubin levels).
 Biliary obstruction (elevated direct serum bilirubin levels).
 Prepare the patient for additional testing as indicated.

Bilirubin (Serum)
 Exposure of the sample to direct sunlight or ultraviolet light
(possible decrease).
 Barbiturates and sulfonamides (possible decrease).
 Precautions
 Protect the sample from strong sunlight and ultraviolet light.
 Handle the sample gently.

Bilirubin (Serum)
 Explain to the patient that the bilirubin test is used to evaluate
liver function and the condition of red blood cells.
 Inform the patient that the test requires a blood sample from a
venipuncture.
 Advise the patient that he may experience slight discomfort
from the tourniquet and needle puncture.
 Inform the patient that he doesn’t need to restrict fluids, but
should fast for at least 4 hours before the test.

Bilirubin (Serum)
 After the Test
stops.
 Assess the venipuncture site for hematoma formation; if one
develops, apply direct pressure.

Coagulation Studies
 Coagulation testing is useful for assessing patients' ability to
clot; for investigating the cause of a patient's coagulopathy;
and for therapeutic monitoring of certain anticoagulant
medications.
 The classical coagulation profile includes:
 Prothrombin time (PT)
 Activated partial thromboplastin time (PTT).

Partial Thromboplastin Time (PTT)
 Description
 Also called the activated partial thromboplastin test (APTT).
 The partial thromboplastin time (PTT) test is used to evaluate
all the clotting factors of the intrinsic pathway, except
platelets, by measuring the time required for formation of
a fibrin clot after calcium and phospholipid emulsion is
added to a plasma sample.

 Purpose
 To screen for clotting factor deficiencies in the intrinsic
pathways.
 To monitor response to heparin therapy.
 21 to 35 seconds (SI, 21–35 seconds)
 Therapetic heparin therapy: 2 to 2.5 times normal limit

 Certain plasma clotting factor deficiencies.
 Presence of heparin.
 Vitamin K deficiency.
 Genetic or acquired deficiency of clotting factors
 Hemophilia A
 Prepare to adjust the patient’s anticoagulant therapy as
indicated.

 Extensive cancer
 Prepare to adjust the patient’s anticoagulant therapy as
indicated.

 Precautions
 To prevent hemolysis, avoid excessive probing at the
venipuncture site and handle the sample gently.

 Explain to the patient that the PTT test is used to determine if
blood clots normally.
 When appropriate, tell the patient receiving heparin therapy
that this test may be repeated at regular intervals to assess
his response to treatment.
 Do not draw from a closed-loop blood sampling system in an
arterial line where heparin flush has been used. Do not draw
from an arm into which heparin is infused.

 During the Test
 Completely fill the collection tube, invert it gently several
times, and send it on ice to the laboratory
 After the Test
 Ensure subdermal bleeding has stopped before removing
pressure.
 For a patient on anticoagulant therapy, apply additional
pressure at the venipuncture site to control bleeding.

Prothrombin Time (PT)
 Description
 PT measures the time required for a fibrin clot to form in a
citrated plasma sample after the addition of calcium ions and
tissue thromboplastin (factor III).
 Purpose
 To evaluate the extrinsic coagulation system (factors V, VII,
and X, and prothrombin and fibrinogen)
 To monitor response to oral anticoagulant therapy

 10 to 14 seconds (SI, 10–14 seconds)
 For a patient receiving oral anticoagulants: 1 to 2½ times the
normal control value.
 Abnormal Findings
 Prolonged prothrombin time (PT) (exceeding 2½ times the
control value; may result from deficiencies in fibrinogen,
prothrombin, vitamin K, or factor V, VII, or X)
 Prepare to adjust the patient’s anticoagulant dosage as
indicated.

 Salicylates, more than 1 g/day (increase).
 Antihistamines, corticosteroids, digoxin (Lanoxin), diuretics,
vitamin K (possible decrease).
 Heparin IV (within 5 hours of sample collection) vitamin A, or
alcohol in excess (prolonged PT).
 Antibiotics, barbiturates (possible increase or decrease).

 Precautions
 To prevent hemolysis, avoid excessive probing during
venipuncture and handle the sample gently.

 Explain to the patient that the PT test is used to determine if
the blood clots normally. When appropriate, explain that this
test is used to monitor the effects of oral anticoagulants.
 The test will be performed daily when therapy begins and will
be repeated at longer intervals when medication levels
stabilize.

 Notify the laboratory and practitioner of medications the
be restricted.
 During the Test
 Completely fill the collection tube and invert it gently several
times to mix the sample and the anticoagulant thoroughly.

 After the Test
stops.
 If a hematoma develops at the venipuncture site, apply
 Tell the patient that he may resume his usual diet and
medications discontinued before the test, as ordered.

Electrolyte
 Electrolytes are involved in many essential processes in your
body.
 They play a role in conducting nervous impulses, contracting
muscles, keeping you hydrated and regulating your body’s pH
levels.
 Electrolytes found in your body include:
 Sodium
 Potassium
 Chloride
 Calcium
 Magnesium
 Phosphate
 Bicarbonate

Sodium, Serum
 Purpose
 To evaluate fluid, electrolyte, and acid–base balance and
related neuromuscular, renal, and adrenal functions.
 Adults and children: 135 to 145 mEq/L (SI, 135–145 mmol/L)

Sodium, Serum
 Critical Values
 Less than 120 mEq/L (SI, 120 mmol/L) or
 greater than 160 mEq/L (SI, greater than 160 mmol/L)

Sodium, Serum
 Abnormal Findings - Elevated Levels (Hypernatremia)
 Diabetes insipidus
 Impaired renal function
 Prolonged hyperventilation
 Excessive sodium intake

Sodium, Serum
 Observe the patient for hypernatremia (Na+ greater than 135)
and associated water loss, signs of thirst, restlessness, dry
and sticky mucous membranes, flushed skin, oliguria, and
diminished reflexes.
 If increased total body sodium causes water retention,
observe for hypertension, dyspnea, edema, and heart failure.

Sodium, Serum
 Decreased Levels (Hyponatremia)
 Sweating
 GI suctioning
 Diuretic therapy
 Diarrhea
 Vomiting
 Burns

Sodium, Serum
 Nursing Implications - Decreased Levels
 In the patient with hyponatremia, watch for apprehension,
headache, decreased skin turgor, abdominal cramps, and
tremors that may progress to seizures.

Sodium, Serum
 Most diuretics (decrease by promoting sodium excretion).
 Corticosteroids (increase by promoting sodium retention).
 Antihypertensives (possible increase due to sodium and water
retention)

Sodium, Serum
 Precautions
 Explain to the patient that the serum sodium test is used to
determine the sodium content of the blood.

Sodium, Serum
 After the Test
stops.
pressure.
 Instruct the patient to resume any medications that were
discontinued before the test, as ordered.

Potassium, Serum
 Purpose
 To evaluate clinical signs of potassium excess (hyperkalemia)
or potassium depletion (hypokalemia).
 To monitor renal function, acid–base balance, and glucose
metabolism.
 To evaluate neuromuscular and endocrine disorders.
 To detect the origin of arrhythmias.

Potassium, Serum
 3.5 to 5 mEq/L (SI, 3.5–5 mmol/L).
 Abnormal Findings - Elevated Levels (hyperkalemia)
 Burn injuries.
 Diabetic ketoacidosis.
 Large blood transfusions.
 Myocardial infarction.
 Renal failure.
 Anemia.

Potassium, Serum
 Nursing Implications - Elevated Levels
 Report abnormal findings to the practitioner
 Observe the patient with hyperkalemia for weakness, malaise,
nausea, diarrhea, colicky pain, muscle irritability progressing
to flaccid paralysis, oliguria, and bradycardia.
 Observe the electrocardiogram (ECG) changes

Potassium, Serum
 Cushing’s syndrome.
 Body fluids loss (such as long term diuretic therapy, vomiting,
or diarrhea).
 Draining wounds.
 Cystic fibrosis.
 Severe burns.
 Diuretic, antibiotic.

Potassium, Serum
 Nursing Implications - Decreased Levels
 Observe the patient with hypokalemia for decreased reflexes;
a rapid, weak, irregular pulse; mental confusion; hypotension;
anorexia; muscle weakness; and paresthesia.
 Monitor the ECG changes.

Potassium, Serum
 Repeated clenching of the fist before venipuncture (possible
increase).
 Excessive or rapid potassium infusion, spironolactone or
penicillin (increase)
 Insulin and glucose administration; diuretic therapy
(especially with thiazides decrease)

Potassium, Serum
 Precautions
 Draw the sample immediately after applying the tourniquet
because a delay may increase the potassium level.
 In severe cases, ventricular fibrillation, respiratory paralysis,
and cardiac arrest can develop. (Cardiac arrest may occur
without warning.)

Potassium, Serum
 Explain to the patient that the serum potassium test is used to
determine the potassium content of blood.
 Advise the patient that the test requires a blood sample.
Explain that he may experience slight discomfort from the
needle puncture and the tourniquet.

Potassium, Serum
 After the Test
stops.
pressure.
 Tell the patient to resume medications that were discontinued
before the test, as ordered.

Reference
 Brunner & Suddarth’s. (2010). Handbook of Laboratory and Diagnostic Tests.
Wolters Kluwer Health, Lippincott Williams & Wilkins.

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