Introduction to Laboratory Tests Handout Version - Copy

8/13/2019 Introduction to Laboratory Tests Handout Version - Copy

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Introduksi

Joel N. Kniep, M.D.

Dept. of Pathology


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Objectives

Introduce vital signs and their use inclinical practice

Introduce basic laboratory tests and theiruse in clinical practice

Discuss normal values and testinterpretation


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Clinical Vital Signs (Vitals)

Temperature Pulse rate

Respiration rate (RR) Blood pressure (bp)


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Temp

Measure of bodys core temp (temp ofinternal organs) in F (or C)

Locations: oral, rectum, axilla, ear Rectal = 0.5 0.7 F higher than oral temp Axilla = 0.3 0.4 F lower than oral temp

Normal: 97.8 99 F (36.5 37.2 C) Critical: > 98.6 F orally or 99.8 F rectally(pyrexia [fever]); < 95 F (hypothermia)


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Pulse rate

Heart rate (HR) or number of heartbeats/min

Normal: 60 100/min (tachycardia): Na + intake, Na + loss,

Excessive free body H 2O loss

(bradycardia): Na+

intake, Na+

loss, free body H 2O


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RR

Number of breaths/min At rest Also note breathing effort or difficulty

Normal: 15 20/min Critical: < 12 or > 25 (hyperventilation): Na + intake, Na +

loss, Excessive free body H 2O loss (hypoventilation): Na + intake, Na +

loss, free body H 2O


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Bp Measures the force of blood against the arterial vessel

walls Measured while seated, after resting for 5 mins, arm resting @

heart level (if possible) Reported as a fraction (systolic/diastolic) & consists of 2

separate measurements: Systolic pressure within artery during cardiac contraction Diastolic pressure within artery during cardiac relaxation and filling

Normal: < 120 mm Hg systolic and < 80 mm Hg diastolic Critical: > 220 mm Hg systolic or > 125 mm Hg diastolic

(hypertension [htn]): Na + intake, Na + loss,Excessive free body H 2O loss (hypotention): Na + intake, Na + loss, free body

H2O


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Complete Blood Count (CBC)

Provides information on cellularcomponents of blood

Includes RBC count, Hemoglobin (Hgb),Hematocrit (Hct), RBC indices, Whiteblood cell (WBC) count and differential,Platelet count


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Total WBCs (leukocytes) Measurement of total WBC count

Consists of total # of WBCs/mm 3 of peripheral venous blood Part of routine testing Useful for evaluation of infection, neoplasm, allergy &

immunosuppression

Normal: 4,000 10,000/mm 3 Critical: < 2,500 or > 30,000/mm 3 (leukocytosis): infection, malignancy, trauma, stress,

hemorrhage, tissue necrosis, inflammation, dehydration,thyroid storm

(leukopenia): drug toxicity, bone marrow failure,overwhelming infections, dietary deficiency, congenitalmarrow aplasia, bone marrow infiltration, autoimmunedisease, hypersplenism


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Erythrocyte count (RBC) Measures # of circulating RBCs/mm 3 of peripheral

venous blood Direct measure of RBC count Part of routine testing and anemia evaluation

Normal: 3.5 5.5 x 10 6/L : erythrocytosis, congenital heart disease, severe

COPD, polycythemia vera, severe dehydration,hemoglobinopathies

: anemia, hemoglobinopathy, hemorrhage, bonemarrow failure, renal disease, leukemia, prostheticvalves, normal pregnancy, multiple myeloma, Hodgkindisease, lymphoma, dietary deficiency


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Hgb Measures total amount of Hgb in blood

Indirect measure of RBC count Part of routine testing and anemia evaluation

Normal: 12 15 g/dL Critical: < 5 or > 20 g/dL : erythrocytosis, congenital heart disease, severe

COPD, polycythemia vera, severe dehydration: anemia, hemoglobinopathy, hemorrhage, bone marrow

failure, renal disease, leukemia, prosthetic valves,normal pregnancy, multiple myeloma, Hodgkin disease,lymphoma, dietary deficiency


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Hct Measure of RBC percent of total blood vol

Indirect measure of RBC # & volume Part of routine testing and anemia evaluation

Normal: 36 48% Critical: < 15% or > 60% : erythrocytosis, congenital heart disease, severe

COPD, polycythemia vera, severe dehydration : anemia, hemoglobinopathy, hemorrhage, bone

marrow failure, renal disease, leukemia, prostheticvalves, normal pregnancy, multiple myeloma, Hodgkindisease, lymphoma, dietary deficiency


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RBC indices

Measures size and hgb content of RBCs Used to classify anemias

Includes Mean corpuscular volume (MCV),mean corpuscular hemoglobin (MCH),mean corpuscular hemoglobinconcentration (MCHC), red blood celldistribution width (RDW)


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MCV Measure of average volume/size of single RBC

MCV = Hct (%) x 10/RBC (million/mm 3) Useful in anemia classification

Normal: 80 100 mm 3

(macrocytic): pernicious anemia (vit B 12 deficiency),folic acid deficiency, antimetabolic therapy, alcoholism,chronic liver disease, hypothyroidism

Normocytic: bone marrow failure/replacement, acuteblood loss, chronic diseases, hemolytic anemias

(microcytic): Fe deficiency anemia, thalassemia,anemia of chronic illness


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MCH

Measure of average amount of hgb withina single RBC MCH = Hgb (g/dL) x 10/RBC (million/mm 3) Provides little additional info to other indices

Normal: 24 32 pg

: macrocytic anemias : microcytic anemia, hypochromic

anemia


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RDW

Measure of variation of RBC size(indicator of degree of anisocytosis) Useful in anemia classification

Normal: variation of 11.5 16.9%

: Fe deficiency anemia, vit B 12 or folatedeficiency anemia, hemoglobinopathies,hemolytic anemias, posthemorrhagicanemias


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Platelet count Measurement of platelets (thrombocytes)

Consists of actual # of platelets/mm 3 of peripheral venous blood Part of routine testing Useful for evaluation of petechiae, spontaneous bleeding, increasingly

heavy menses or thrombocytopenia Useful for monitoring discourse/therapy of thrombocytopenia/bone

marrow failure Normal: 150,000 400,000/mm 3 Critical: < 50,000 or > 1,000,000/mm 3 (thrombocytosis): malignant disorders, polycythemia vera,

postsplenectomy syndrome, rheumatoid arthritis, Fe deficiencyanemia

(thrombocytopenia): Hypersplenism, hemorrhage, immunethrombocytopenia, leukemia & other myelofibrosis disorders, TTP,DIC, SLE, chemotherapy, pernicious anemia


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WBC definitions

Leukocytosis abnormally large numberof leukocytes; generally indicated by WBCcount of 10,000 cells/mm3

Lymphocytosis form of actual or relativeleukocytosis due to increase in numbers oflymphocytes

Left shift increase in the number ofimmature neutrophils (bands/stabs) foundin the blood


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WBC differential

Measurement of percentage of each WBC typein specimen Useful for infection, neoplasm, allergy &

immunosuppression evaluations Normal: Neutrophils (50 70%), Lymphocytes

(20 40%), Monocytes (2 8%), Eosinophils (0 5%), Basophils (0 2%)

: refer to individual cell types on chart : refer to individual cell types on chart


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Basic Metabolic Panel (BMP)

Measures electrolytes, chemicals,metabolic end products & substrates

Consists of Glucose, Blood Urea Nitrogen(BUN), Creatinine, Na +, K+, Cl -,Bicarbonate (HCO 3-), Ca 2+


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Glucose Direct measure of blood glucose

Commonly used to evaluate diabetic pts Part of routine testing

Normal: 70 - 100 mg/dL

Critical: < 50 and > 400 mg/dL ( ) or < 40 and > 400mg/dL ( )

(hyperglycemia): DM, acute stress response, Cushingsyndrome, pheochromocytoma, chronic renal failure,acute pancreatitis, acromegaly, corticosteroid therapy

(hypoglycemia): insulinoma, hypothyroidism,hypopituitarism, Addison disease, extensive liverdisease, insulin overdose, starvation


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BUN Measures urea nitrogen in blood

End product of protein metabolism (produced in liver) Indirect measure of renal function & glomerular function

(excretion) Measure of liver metabolic function

Part of routine labs Usually interpreted along with Cr (less accurate than Cr for renal

disease) Normal: 6 -21 mg/dL Critical: > 100 mg/dL : prerenal causes, renal causes, postrenal azotemia : liver failure, overhydration because of SIADH, neg

nitrogen balance, pregnancy, nephrotic syndrome


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Creatinine Measures serum creatinine

Catabolic product of creatine phosphate (skeletal musclecontraction)

Excreted entirely by kidneys direct measure of renal function Minimally affected by liver function

Elevation occurs slower than BUN Doubling 50% reduction in GFR

Normal: 0.44 1.03 mg/dL Critical: > 4 mg/dL : diseases affecting renal function (glomerulonephritis,

pyelonephritis, ATN, urinary tract obstruction, reducedrenal blood flow, diabetic nephropathy, nephritis),rhabdomyolysis, acromegaly, gigantism

: debilitation, decreased muscle mass


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K+

Measures serum potassium level Major cation within cell

Normal: 3.4 5.2 mEq/L

Critical: < 2.5 or > 6.5 mEq/L (hyperkalemia): excessive intake, acidosis,acute/chronic renal failure, Addison disease,hypoaldosteronism, infection, dehydration

(hypokalemia): deficient intake, burns,hyperaldosteronism, Cushing syndrome, RTA,licorice ingestion, alkalosis, renal artery stenosis


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Cl-

Measures serum chloride level Major anion in EC space Helps maintain electrical neutrality; follows sodium

Normal: 98 108 mEq/L

Critical: < 80 or > 115 mEq/L (hyperchloremia): dehydration, metabolic acidosis,

RTA, Cushing syndrome, renal dysfunction, respiratoryalkalosis, hyperparathyroidism

(hypochloremia): overhydration, SIADH, CHF, chronicrespiratory acidosis, metabolic alkalosis, Addisondisease, Aldosteronism, vomiting/prolonged gastricsuction, hypokalemia


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HCO 3-

Measures CO 2 content of blood Major role in acid-base balance Regulated by kidneys Used to evaluate pt pH status & electrolytes

Normal: 22 32 mEq/L Critical: < 6 mEq/L : severe vomiting, high -volume gastric suction,

aldosteronism, mercurial diuretic use, COPD, metabolicalkalosis

: chronic diarrhea, chronic loop diuretic use, renalfailure, DKA, starvation, metabolic acidosis, shock


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Ca 2+

Measures serum calcium level Direct measurement Used to evaluate parathyroid function & Ca metabolism Used to monitor renal failure, renal transplantation,

hyperparathyroidism, various malignancies, & Ca level when givinglarge-volume blood transfusions

Normal: Total = 8.3 10.3 mg/dL, Ionized = 4.5 5.6 mg/dL Critical: Total < 6 or > 13 mg/dL, Ionized < 2.2 or > 7 mg/dL (hypercalcemia): hyperparathyroidism, bone mets, Paget disease

of bone, prolonged immobilization, milk-alkali syndrome, vit Dintoxication, hyperthyroidism

(hypocalcemia): hypoparathyroidism, renal failure, rickets, vit Ddeficiency, osteomalacia, pancreatitis, alkalosis, malabsorption, fatembolism


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Comprehensive Metabolic Panel(CMP)

Includes all components of BMP plus Albumin, Total protein, Alkalinephosphatase (ALP), Alanineaminotransferase (ALT), Aspartateaminotransferase (AST) and Bilirubin


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Albumin Measures amount of albumin in blood

Formed within liver & comprises 60% of total protein in blood Maintains colloidal osmotic pressure & transports blood

constituents Measure of both hepatic function and nutritional state

Normal: 3.5 5 g/dL : dehydration : malnutrition, pregnancy, liver disease, protein -losing

enteropathies, protein-losing nephropathies, 3 rd spacelosses, overhydration, capillary permeability,inflammatory disease, familial idiopathic dysproteinemia


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Total Protein

Measures total protein in blood Combination of prealbumin, albumin &

globulins

Normal: 6.4 8.3 g/dL


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ALP

Measures serum ALP concentration Detect & monitor liver and bone disease

Normal: 30 -120 units/L : 1 cirrhosis, intrahepatic/extrahepatic biliary

obstruction, 1 /metastic liver tumor,hyperparathyroidism, Paget disease, normalgrowing bones in children, bone mets, RA, MI,sarcoidosis, healing fracture, normal pregnancy,

intestinal ischemia or infarction : hypophosphatemia, malnutrition, milk -alkalisyndrome, pernicious anemia, scurvy


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ALT Found predominantly in liver

Injury/disease to parenchyma release into blood ID & monitor hepatocellular diseases of liver If jaundiced, implicates liver rather than RBC hemolysis

Normal: 4 36 international units/L @ 37 C Sig : hepatitis, hepatic necrosis, hepatic ischemia Mod : cirrhosis, cholestasis, hepatic tumor, hepatotoxic

drugs, obstructive jaundice, severe burns, trauma tostriated muscle

Mild : myositis, pancreatitis, MI, infectious mono, shock


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AST

Found in highly metabolic tissue (cardiac &skeletal muscle, liver cells) Disease/injury lysing of cells & release into blood Elevation proportional to # of cells injured

Used for evaluation of suspected coronary arterydisease or hepatocellular disease Normal: 0 35 units/L : heart diseases, liver diseases, skeletal

muscle diseases : acute renal disease, beriberi, DKA,pregnancy, chronic renal dialysis


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Bilirubin

Measures level of total bilirubin in blood End product of RBC metabolism (RBCs Hgb

Heme (+ globin) Biliverdin Bilirubin(unconjugated/indirect) Bilirubin (conjugated/direct)

Component of bile Consists of conjugated (direct) & unconjugated(indirect) bilirubin

Used to evaluate liver function; hemolytic anemiaworkup in adults & jaundice in newborns

Jaundice occurs when total bilirubin > 2.5 mg/dL Normal: 0.3 1 mg/dL Critical: > 12 mg/dL


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Unconjugated bilirubin

Measures level of indirect bilirubin in blood Normal: 0.2 0.8 mg/dL : erythroblastosis fetalis, transfusion rxn,

sickle cell anemia, hemolytic jaundice,hemolytic anemia, pernicious anemia,large-volume blood transfusion, large

hematoma resolution, hepatitis, cirrhosis,sepsis, neonatal hyperbilirubinemia,Crigler-Najjar syndrome, Gilbert syndrome


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Conjugated bilirubin

Measures level of direct bilirubin in blood Produced by conjugating glucuronide w/

unconjugated/indirect bilirubin in liver

Normal: 0.1 0.3 mg/dL : gallstones, extrahepatic duct

obstruction, extensive liver mets,cholestasis from drugs, Dubin-Johnsonsyndrome, Rotor syndrome


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Urinary Analysis (UA)

Provides information about kidneys &other metabolic processes

Used for diagnosis, screening &monitoring

Frequently used to test for urinary tractinfections (UTIs)


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UA Normal Values

Appearance: clear Color: amber yellow Odor: aromatic

pH: 4.6 8 Protein: 0 8 mg/dL Specific gravity: 1.005 1.030 Leukocyte esterase: negative Nitrites: none Ketones: none


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UA Normal Values cont.

Bilirubin: none Urobilinogen: 0.01 1 Ehrlich unit/mL Crystals: none

Casts: none Glucose: negative White Blood Cells: 0 4/low-power field WBC casts: none Red Blood Cells (RBCs): 2 RBC casts: none


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Urinary Protein

Used to monitor kidney function Normally not present in normal kidney due to

size barrier in glomerulous

Normally tested by dipstick method,quantification requires 24-hour urine collection

Presence (proteinuria) can indicate nephroticsyndrome, multiple myeloma or complications ofDM, glomerulonephritis, amyloidosis


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Urinary Ketones

End products of fatty acid catabolism Examples: -hydroxybutyric acid,

acetoacetic acid, acetone Associated with poorly controlled diabetes Used to evaluate ketoacidosis associated

w/ alcoholism, fasting, starvation, high-protein diets, isopropanol ingestion


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Cerebral Spinal Fluid (CSF) Analysis

Collected via lumbar puncture (LP) Useful for the diagnosis of 1 or metastatic

brain/spinal cord neoplasm, cerebralhemorrhage, meningitis, encephalitis,degenerative brain disease, autoimmunediseases w/ CNS involvement,

neurosyphilis, demyelinating diseases


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CSF analysis Normal Values

Opening pressure:


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CSF analysis Normal Values cont.

Protein: 15 45 mg/dL Glucose: 50 75 mg/dL or 60 70% of

blood glucose level


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CSF WBC count

Pleocytosis turbidity of CSF due toincreased #s of cells


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CSF PMNs

Causes of PMNs: bacterial meningitis,tubercular meningitis, cerebral abscess,subarachnoid bleeding, tumor


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CSF Lymphs

Causes of lymphs/plasma cells: viral,tubercular, fungal or syphilitic meningitis;multiple sclerosis (MS), Guillain-Barrsyndrome


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CSF Monos

Causes of monos: tubercular or fungalmeningitis, hemorrhage, brain infarction


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CSF ProfileRBCs/mm3

WBCs/mm 3

Glucose(mg/dL)

Protein(mg/dL)

Openingpressure

(cm H 2O)

Appearance

-globulin(%

protein)Bacterialmeningitis

(> 1,000PNMs)

(< 45mg/dL)

(> 250mg/dL)

Cloudy

Viralmeningitis

(lymphs/monos)

Asepticmeningitis

SAH

Guillain-Barrsyndrome

MS Normal in2/3 pts; >15 in < 5%of pts

Pseudotumorcerebri


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Additional Resources

Corbett, J.V. (2008). Laboratory Tests and Diagnostic Procedureswith Nursing Diagnoses 7 th Edition. Upper Saddle River: PrenticeHall.

Fischbach, F.T. & Dunning, M.B. (2008). A Manual of Laboratory &Diagnostic Tests 8 th Edition. Philadelphia: Lippincott Williams &Wilkins.

Jacobs, D.S., De Mott, W.R. & Oxley, D.K. (2001). Jacobs & DeMottLaboratory Test Handbook with Key Word Index 5 th Edition. Hudson:Lexi Comp, Inc.

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests 4 th Edition.St. Louis: Saunders Elsevier.

Young, R.H. & Hicks, J. (2002). Directory of Rare Analyses 2000-2002. St. Louis: AACC Press.

http://www.labtestsonline.org/
http://www.labtestsonline.org/http://www.labtestsonline.org/


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Special Thanks

Dr. Amira F. Gohara, M.D. Dr. Carol Bennett-Clarke, Ph.D. Dr. Constance Shriner, Ph.D.

Cynthia R. OConnell, BSMT (ASCP)

Introduction to Laboratory Tests Handout Version - Copy

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