laboratory data(1)l

7/27/2019 Laboratory Data(1)l

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LABORATORY DATA

The most frequently used laboratory tests are complete blood count, electrolytes, blood chemistries and

urinalysis.

Normal values may vary from lab to lab depending on techniques and reagents used. Normal values may

also vary depending on patients age, gender, weight, height and other factors. Laboratory error is an uncommon error however it can happen. The following are some potential causes

of laboratory error:

Technical Error. Spoiled Specimen. Specimen Taken At Wrong Time. Incomplete Specimen. Faculty Reagents. Diet; e.g. red meat consumption may cause a false positive hem-occult stool test. Medications; e.g. iron supplements may cause a false positive hem-occult tool test.

If laboratory error is suspected the test should be repeated.

Important laboratory tests include the following:

Hematology Urinalysis Electrolytes and blood chemistry Cardiac diagnostic tests Lipoprotein panel Endocrine diagnostic testso Thyroid function tests

o Diabetes mellituso Adrenal gland tests

Gastrointestinal/hepatic/pancreatic diagnostic tests Coagulation tests Immunologic diagnostic tests Infectious disease diagnostic tests Hepatitis a Hepatitis b Hepatitis c


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HEMATOLOGY

The complete blood count (CBC) is an extremely common laboratory test that provides values

for the following

Hemoglobin. Hematocrit. Red Blood Cells. Mean Corpuscular Cell Volume. Mean Corpuscular Cell Hemoglobin. Mean Corpuscular Hemoglobin Concentration. Reticulocytes. White Blood Cells. Neutrophils. Lymphocytes. Monocytes. Eosinophils. Basophils. Platelets.


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1. HEMOGLOBIN: (Hb)

Hemoglobin is the oxygen carrying compound found in the RBCs. Hemoglobin level is a direct indicatorof the oxygen carrying capacity of the blood.

Adaptation to high altitudes, extreme exercise and pulmonary conditions may causes variations inhemoglobin values.

International Units SI Units Increased Value Decreased Value

Male 1418 g/dl

Female 1216 g/dl

8.711.2 mmol/L

7.49.9 mmol/L

Hemoglobin values maybe increased in diseases

such as Polycythemia

Vera and ChronicObstructive Lung Disease.Hemoglobin may also be

increased in chronicsmokers and individuals

who engage vigorousexercise or live at high

altitudes.

Hemoglobin isdecreased in anemia

of all types,

particularly IronDeficiency Anemia.Hemoglobin is also

reduced with Bloodloss, Hemolysis,

pregnancy, fluidreplacement or

increased fluid intake.

2. HEMATOCRIT: (Hct)

The Hematocrit value describes the volume of blood that is occupied by RBCs. It is expressed as a

percentage of total blood volume. Another name for hematocrit is packed cell volume. The value ofhematocrit is generally about three times the value of hemoglobin.


Male 4252%

Female 3747%

0.420.

0.370.47 52

Increases in hematocritvalue are associated with

Polycythemia Vera,chronic obstructive lung

disease and individualswho live at highaltitudes. Increased

hematocrit may also beseen in cases of

dehydration and shock.

Hemtocrit is decreasedin anemia of all types.

Hematocrit is alsoreduced with blood

loss, hemolysis,pregnancy, cirrhosis,hyperthyroidism and

leukemia.


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3. RED BLOOD CELLS:(RBCs)

RBCs are produced in the bone marrow. They are released into the systemic circulation and serve totransport oxygen from the lungs to the body tissues. After circulating for a life span of 120 days the

RBCs are cleared by the Reticulo-endothelial system.


Male 4.35.9 x 106cells/mm

3

Female 3.55.5 x

106 cells/mm3

4.35.9 x 1012cells/L

3.55.5 x 1012 cells/L

Increased RBCs countsare associated with

Polycythemia Vera, highaltitude and strenuous

exercise.

Red blood cell countsare decreased in various

types of anemias.

4. MEAN CORPUSCULAR CELL VOLUME: (MCV)

MCV provides an estimate of the average volume of the erythrocyte. Higher the MCV, the larger theaverage size of the RBCs. Cells with an abnormally large MCV are classified asMACROCYTICand

cells with a low MCV are referred to asMICROCYTIC. NORMOCYTICRBCs have an MCV that fallswithin the normal range.


7696 um3/cell 7696 fL An increase in MCV is

associated with folatedeficiency, B12

deficiency, alcoholism,chronic liver disease,

hyperthyroidism and useof medications such asValproic Acid, AZT,

Stavudine and Anti-metabolites.

Decreased MCV mayresult from iron

deficiency anemia,

hemolytic anemia, leadpoisoning andThalassemia.


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5. MEAN CORPUSCULAR CELL HEMOGLOBIN: (MCH)

MCH indicates the average weight of hemoglobin in the RBCs. Cells with a low MCH are pale in colorand are referred asHYPOCHROMIC. Cells with an increased MCH are HYPERCHROMIC.

International Units Increased Value Decreased Value

2733 pg/cell Elevated MCH may be caused by folate

deficiency. In hyperlipidemia MCH maybe falsely elevated because of specimen

turbidity.

Decreased MCH is associated

with iron deficiency anemia.

6. MEAN CORPUSCULAR CELL HEMOGLOBIN CONCENTRATION: (MCHC)

MCHC is a measure of average hemoglobin concentration concentration in the RBCs.


3236 g/dL SI 320360 g/L Increased MCHC is

associated withhereditary spherocytosis.

MCHC may be

decreased in irondeficiency anemia,

hemolytic anemia, leadpoisoning and

thalassemia.


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7. RETICULOCYTES:

Reticulocytes are immature RBCs formed in the bone marrow. An increase in reticulocytes usuallyindicates an increase in RBCs production but may also be an indicative of a decrease in the circulating

number of mature erythrocytes.


0.52 % of RBC SI 0.0050.02 RBC Increased reticulocytecounts are associated

with hemolytic anemia,hemorrhage and sicklecell disease. Increased

reticulocytes are also

indicative of response totreatement of Anemias

secondary to irondeficiency, B12

deficiency or FolateDeficiency.

Reticulocytes may bedecreased as a result ofinfectious causes, renal

disease, toxins, irondeficiency anemia and

drug induced bone

marrow depression.

8. WHITE BLOOD CELLS :(WBCs)

The WBC count represents the total number of WBCs in a given volume of blood. Mature WBCs existin many forms including Neutrophils, Lymphocytes, Monocytes, Eosinophils and Basophils.


3,200 10,000

cells/mm33.210.0 x 109 cells/L An increase in WBC

count is referred to asLEUKOCYTOSIS.

Leukocytosis may be

caused by infection,Leukemia, Trauma and

Corticosterio use.Emotion, stress and

seizures may alsoincrease WBC count.

A decrease in WBC

count is referred to asLEUKOPENIA.

Decreased WBCs may

be seen in Viralinfection, AplasticAnemia and use ofChemotherapy or

Anticonvulsants.


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9.NEUTROPHILS:

Neutrophils are the most common type of WBC. Their primary function is to fight bacterial and fungalinfections by phagocytizing foreign particles. Neutrophils may also be involved in the pathogenesis of

some inflammatory disorders, e.g. Rheumatoid Arthritis and Inflammatory Bowel Disease.


Segs 3673%

Bands 35%

0.030.05

0.360.73

An increase incirculating neutrophils iscalledNEUTROPHILIA.

Neutrophilia is

associated withinfection, metabolic

disorders (e.g. diabetic

ketoacidosis), uremia,response to stress,

emotional disturbances,burns, acute

inflammation and use of

medications such ascorticosteroids.

A decrease in thenumber of circulatingneutrophils is called as

NEUTROPENIA.

Neutropenia may resultfrom viral infectionse.g. Momonucleosis,

Hepatitis, Septicemia,overwhelming

infections and use ofchemotherapy agents.

Bands are immature neutrophil s.

An increase in bands often referred to as a shift to the left during infection or leukemia.


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10. LYMPHOCYTES:

Lymphocytes are the second most common type of circulating WBC. They are important in the immune

response to foreign antigens.


2040 % An elevated lymphocyte count is calledLYMPHOCYTOSIS.

Lymphocytes may be elevated inHepatitis, Mononucleosis, Chickenpox,

Herpes Simplex, Herpes Zoster and otherviral infections. Some bacterial infectionse.g. Syphilis, Brucellosis, Leukemia and

Multiple Myeloma are also associated withlymphocytosis.

A decreased lymphocyte count isreferred to asLYMPHOPENIA.Lymphopenia may result fromacute infections, burns, trauma,

lupus, HIV and lymphoma.

11. MONOCYTES:

Monocytes are synthesized in the bone marrow released into the circulation and subsequently migrate into

lymph nodes, spleen, liver, lungs and bone marrow. In these tissues monocytes mature into macrophagesand serve as scavengers for foreign substances.


28 % An elevated monocyte count is

referred to asMONOCYTOSIS.Monocytosis may be observed in

the recovery phase of someinfections, Sub Acute Bacterial

Endocarditis (SBE), Tuberculosis

(TB), Syphilis, Leukemia,Lymphoma, Lupus, Rheumatoid

Arthritis and Cirrhosis.

A reduced monocyte count is

calledMONOCYTOPENIA.Monocytopenia is usually not

associated with a specificdisease but may be seen with

use of bone marrow suppressive

agents or severe stress.


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12. EOSINOPHILS:

Eosinophils are phagocytic WBCs that assist in the killing of bacteria and yeast. They are also involvedin allergic reactios and in the immune response to parasites.

International Units Increased Value

04 %

An increase in eosinophil count is called asEOSINOPHILIA.

It is associated with allergic disorders, allergic drug reactions,collagen vascular disease, parasitic infections and some

malignancies.

13. BASOPHILS:

Basophils are phagocytic WBCs present in small numbers in the circulating blood. They contain heparin,histamine and leukotrienes. They are probably associated with hypersensitivity reactions.

International Units Increased Value

01 % Increased basophils may be seen in hypersensitivity reactions to food or othermedications, certain leukemias and ulcerative colitis.


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14. PLATELETS:

Platelets are a critical element in blood clot formation. The risk of bleeding is low unless platelets fallbelow 20,00050,000/L.

International units SI units Increased value Decreased value

150,000400,000/L

150400 x 109/L Increased platelets(thrombocytosis,

thrombocythemia) maybe caused by infection,

malignancies,splenectomy, chronic

inflammatory disorders

e.g. rhrumatoid arthritis,

polycythemia vera,severe stress, surgery or

trauma.

Decreased plateletcount

(thrombocytopenia)may occur in

autoimmune disorderssuch as idiopathicthrombocytopenia

purpura (ITP) and also

with aplastic anemia,radiation,

chemotherapy, spaceoccupying lesion in the

bone marrow andheparin or valproic

acid.Aspirin and NSAIDs do

not affect platelet countbut impair the platelet

function.


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URINALYSIS

Urinalysis (UA) is a useful laboratory test that enables the clinician to identify patients with renaldisorders, as well as some non renal disorders.

Common elements included in the UA are

Appearance. pH. Specific Gravity. Protein. Glucose. Ketones. Blood. Bilirubin. Leukocyte esterase. Nitrites.


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1. APPEARANCE:

On visual examination the urine color should range from clear to dark yellow. Some cloudiness is normaland may be caused by phosphates or urates which precipitate as the urine cools to room temperature.Abnormal appearances of urine include the following

Red Orange color may be caused by presence of myloglobin (from muscle breakdown, fromseizures, cocaine or injuries), hemoglobin, medications (Rifampicin, Phenothiazines,Phenazopyridine, Phenolphthalein), or foods (beets, carrots, blackberries).

Blue Green color may result from methylene blue or ingestion of beets. Brown Blackcolor may be associated with presence of myoglobin or porphyrins from porphyria

or sickle cell.

Foamy urine indicates the presence of protein or bile acids.

2. SPECIFIC GRAVITY:

Specific gravity is an indication of the ability of the kidney to concentrate urine. Unusually low specific

gravity would suggest that the kidneys are not able to concentrate urine appropriately.

Normal Range Increased Value Decreased Value

1.0101.025 Increased specific gravity may beassociated with dehydration,

excretion of radiologic contrastmedia or SIADH. In addition,

increased excretion of glucose orprotein greater than 2g per daymay also increase urine specific

gravity.

Decreased specific gravity mayoccur in chronic renal failure or

diabetes insipidus.

3. pH:

Normal urine specimens are acidic. The normal urine pH is approximately 6.

Normal Range Clinical Significance

4.58 Alkaline urine may befound in certain urinary tract infections e.g. infections caused by urea

splitting organisms E. coli, Proteus, Klebsiella, renal tubular acidosis andwith the use of acetazolamide or thiazide diuretics.


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4. PROTEIN:

Trace protein in the urine is a common clinical finding and often has no clinical significance.

5. GLUCOSE AND KETONES:

Glucose begins to spill into urine when serum blood glucose is greater than 180.

6. BLOOD:

Blood in the urine ( hematuria ) may indicate urinary tract damage.


0 (


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7. BILIRUBIN:

Bilirubin in the urine usually produces a dark yellow or brown color.

8. LEUKOCYTE ESTERASE:

Positive leukocyte esterase provides an indication of WBCs in the urine.

9. NITRITES:

Gram negative bacteria are capable of converting dietary nitrates to nitrites.


Zero to Trace. Bilirubin in the urine may be associated with liver diseases (e.g. hepatitis) or

obstructive biliary tract disease. Phenazopyridine or phenothiazines may causea false positive result for bilirubin in the urine.


Zero to Trace. Leukocyte esterase in the urine is associated with infections and/or

inflammation of the urinary tract.


Negative. Presence of nitrites in the urine suggests colonization or infection with gram

negative organisms


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ELECTROLYTES AND BLOOD CHEMISTRY

It includes the following Sodium. Potassium. Chloride. Carbon Dioxide. Anion Gap. Glucose Blood Urea Nitrogen. Creatinine Calcium.

Inorganic Phosphorus. Magnesium Uric acid Osmolarity Total Serum Protein


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1. SODIUM: (Na+)

Sodium is the most prevalent cation in the extracellular fluid. Sodium is important in regulating serumosmolarity, fluid balance and acid base balance. In addition sodium also assists in maintaining the electric

potential necessary for necessary for transmission of nerve impulses.


135147 mEq/L Increased sodium(HYPERNATREMIA) may result

from increased sodium intake orincreased fluid loss. Fluid loss fromgastroenteritis, diabetes insipidus,

Cushings disease,hyperaldosteronism and

administration of hypertonic saline

solution are causes ofhypernatremia.

Decreased sodium(HYPONATREMIA) may be

caused by a decrease in total bodysodium but is more commonly

attributed to excess accumulationof body water (DILUTIONAL

HYPONATREMIA).

Common causes of dilutional

hyponatremia include CHF,cirrhosis and nephrotic syndrome.

Sodium depletion may also be seenin SIADH, cystic fibrosis,

mineralocorticoid deficiency orfluid replacement with solutions

that do not contain sodium.SIADH may be associated with the

use of medications includingchlorpropamide, thiazide diuretics

and carbamazepine.


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2.POTASSIUM: (K+)

Potassium is the main intracellular cation. Potassium plays an important role in many body functionsincluding regulation of nevre excitability and muscle function. Cardic function and neuromuscularfunction can be significantly affected by either an increase or decrease in potassium levels.


3.55.0 mEq/L Causes of increased potassium(HYPERKALEMIA) include

metabolic or respiratory acidosis,renal failure, Addisons disease and

massive cell damage from burns,injuries and surgery. Medicationssuch as ACE inhibitors, potassium

supplements and potassium sparing

diuretics are also contributingfactors to hyperkalemia.

Causes of decreased potassium(HYPOKALEMIA) include severe

diarrhea and/or vomiting,alkalosis, hyperaldosteronism,Cushings disease and use of

amphotericin B or thiazide, loopor osmotic diuretics.

3.CHLORIDE:

Chloride primarily serves a passive role in the maintenance of fluid balance and acid base balance. Serumchloride values are useful in identifying fluid or acid base balance disorders.


95105 mEq/L HYPERCHLOREMIA may be seenin metabolic acidosis, respiratory

alkalosis, dehydration and renaldisorders.

HYPOCHLOREMIA may beassociated with prolonged

vomiting, gastric suctioning,metabolic alkalosis, CHF, SIADH

and Addisons disease.


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4. CARBON DIOXIDE: (CO2)

The majority of CO2 in the plasma is present as bicarbonate ions and small percentage is dissolved CO2.The CO2 content is the sum of both bicarbonate ions and dissolved CO2.


22 - 28 mEq/L 95105 mmol/L Increased CO2 is seen inmetabolic alkalosis.

Decreased CO2 isassociated with

metabolic acidosis andhyperventilation.

5. ANION GAP:

Anion gap is calculated using the following formula:

Anion gap = [Na+

- (Cl-+ HCO3

-)]

Anion gap is useful in evaluating causes of metabolic acidosis.


311 mEq/L Anion gap may be increased in conditions such as renal failure, lactic

acidosis, ketoacidosis and salicylate, methanol or ethylene glycoltoxicity.


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6. GLUCOSE:

Glucose is an important energy source for most cellular functions. Blood glucose regulation is achievedthrough a complex set of mechanisms that involves insulin, glucagon, cortisol, epinephrine and otherhormone.


70110 mg/dL(fasting)

3.96.1 mmol/L The most common causeof increased glucose

(HYPERGLYCEMIA) isDIABETES MELITUS.

Causes ofhyperglycemia include

Cushings disease,

sepsis, pancreatitis,

shock, trauma,myocardial infarction

and use ofcorticosteroids or niacin.

HYPOGLYCEMIA mayresult from missing a

meal, oralhypoglycemic agents,

insulin overdose orAddisons disease.

7. BLOOD UREA NITROGEN: (BUN)

Urea nitrogen is an end product of protein catabolism. It is produced in the liver, transported in the bloodand cleared by the kidneys. BUN concentration serves as a marker of renal function.


818 mg/dL 3.06.5 mmol/L Increased BUN may beassociated with acute or

chronic renal failure,CHF, gastrointestinal

bleeding, high proteindiet, shock, dehydration

and nephrotoxic

medications.

Decreased BUN is seenin liver failure because

of inability of the liverto synthesize urea.


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8.CREATININE:

Muscle creatine and phosphocreatine break down to form creatinine. Creatinine is released into the bloodand excreated by glomerular filtration in the kidneys. Thus, serum creatinine is used as a tool to identify

patients with renal dysfunction.


0.61.3 mg/dL 53115 mol/L Increased creatinine isassociated wiyh renal

dysfunction,dehydration, urinary

tract obstruction,increased exercise,hyperthyroidism,

myasthenia gravis and

use of nephrotoxic drugssuch as cisplatin and

amphotericin B.

Serum creatinine maybe reduced in cachexia,

inactive elderly orcomatose patients and

spinal cord injurypatients.

BUN/CREATENINE RATIO:

Calculating the BUN/Creatinine ratio may suggest an etiology for renal dysfunction. A BUN/Creatinineratio greater than 20 suggests a prerenal cause such as GI bleeding. ABUN/Creatinine ratio between 10 and 20 indicates intrinsic renal dysfunction.


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9. CALCIUM: (Ca++

)

Majority of calcium in the body is found in the skeletal bones and teeth. The reminder is found in theblood, muscle and other tissues. In addition to playing a role in bone mineralization, Calcium is importantin cardiac and skeletal muscle contraction, blood coagulation, enzyme activity and transmission of

impulses. In the blood, approximately half of the calcium is in ionized free state and the other half is

bound to proteins or complexed with anions. Only calcium in the Free State may be utilized inphysiologic functions. Calcium levels are regulated by a complex system that involves the skeleton,kidneys, intestines, parathyroid hormone, vitamin D and serum phosphate.


8.510.5 mg/dL 2.12.6 mmol/L The most common causeof increased calcium

(HYPERCALCEMIA) is

malignancies andprimary

hyperparathyroidism.Other causes include

Pagets disease,sarcoidosis, vitamin D

intoxication, milk alkalisyndrome, Addisons

disease and use ofthiazide diuretics and

lithium.

Causes of decreasedcalcium

(HYPOCALCEMIA)

includehypoparathyrodism,

vitamin D deficiency,hyperphosphatemia,

pancreatitis, alkalosis,renal disease and use of

loop diuretics.

PSEUDOHYPOCALCEMIA:

One half of serum calcium circulates bound to plasma proteins such as albumin. A decreased albuminconcentration may lead to a decreased total calcium concentration and calcium levels may appear falsely

low in the presence of low albumin. Serum calcium levels may be corrected for low albumin as follows:

Corrected Calcium = Reported Serum Calcium + 0.8 (4.0patients albumin)


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10. INORGANIC PHOSPHATES:

Phosphate is an intracellular anion involved in several critical physiologic functions. Phosphate isnecessary for formation of the cellular energy source adenosine tri-phosphate (ATP) and the synthesis of

phospholipids. Phosphate also plays a role in protein, fat and carbohydrate metabolism as well as acid

base balance.

International units SI units Increased value Decreased value

2.64.5 mg/dL 0.841.45 mmol/L Increased Phosphate(HYPERPHOSPHATEMIA)

can result from renaldysfunction, increased

vitamin D intake, increased

phosphate intake,

hypoparathyrodism andbone malignancy.

Decreased Phosphate(HYPOPHOSPHATEMIA)

can be associated withoveruse of aluminium and

calcium containing

antacids, alcoholism,

malnutrition andrespiratory alkalosis.

11. MAGNESIUM: (Mg++

)

Magnesium is a necessary cofactor in physiologic functions utilizing ATP. It is also vital in protein andnucleic acid synthesis, as well as neuromuscular function.


1.72.4 mg/dL 0.851.2 mmol/L reased Magnesium(HYPERMAGNESEMIA)

may result from renalfailure or Addisons

disease. In addition, theadministration o Mgsupplements or Mg

containing antacids orlaxatives to patients with

renal dysfunction may

also fesult inhypermagnesemia.

Decreased Magnesium(HYPOMAGNESEMIA)

may be associated withdiarrhea, vomiting,

malabsorption,alcoholism,

hyperaldosteronism,pancreatitis and use ofdiuretics, amphotericin

B or cisplastin.


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12. URIC ACID:

Uric acid is the main metabolic end product of the purine bases of DNA.


Male 3.68.5mg/dL

Female 2.36.6

mg/dL

214506 mol/L

137393 mol/L

Increased uric acid

(HYPERURICEMIA)may be caused by

excessive production of

purines or inability ofthe kidney to excrete

urate. Common causesof hyperuricemia are

renal dysfunction, tumor

lysis syndrome, high

protein diet and use offurosemide, thiazides

and niacin.Hyperuricemia may be

associated with thedevelopment of gouty

arthritis, nephrolithiasisand

Decreased uric acid

(HYPOURICEMIA)levels usually occur

with a low protein diet

or use of allopurinol,probenecid or highdoses of aspirin or

vitamin C.

13. OSMOLALITY:

Plasma osmolality describes the osmotic concentration or number of osmotically active particles in the

plasma. Sodium, glucose and blood urea nitrogen are the main components that determine serumosmolality. The serum osmolality may be calculated as follows:

Serum Osmolality = 1.86 [Na+] + glucose/18 + BUN/2.8


280295 mOsm/kg Increased Serum Osmolality mayoccur with dehydration, diabetic

ketoacidosis (DKA), diabetesInsipidus and ethanol, methanol orethylene glycol toxicity.

Decreased Serum Osmolalitymay be caused by overhydration

or SIADH.


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14. TOTAL SERUM PROTEIN:

Total serum protein is the sum of albumin, globulin and other circulating proteins in the serum. Albuminand globulins are indicators of nutritional status.


6.08.5 g/dL Increased Protein

(HYPERPROTEINEMIA) may beassociated with collagen vascular

diseases (lupus, rheumatoid

arthritis, and scleroderma),sarcoidosis, multiple myeloma and

dehydration.

Decreased Protein

(HYPOPROTEINEMIA) mayresult from a decreased ability tosynthesize protein (liver disease)

or an increased protein wasting asseen in renal disease, nephritic

syndrome and third degree burns.


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CARDIC DIAGNOSTIC TESTS

Following two tests fall into this category

Creatine Kinase Troponin


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1.CREATINE KINASE: (CK)

Creatine Kinase is an enzyme found primarily in skeletal muscles and in smaller fractions in the brain andcardic muscle. CKMB ( cardic tissue) is an important marker in the diagnosis of acute myocardial

infarction ( AMI ).

2. TROPONIN:

Troponin I and T are sensitive markers of cardiac injury.


Total CK

Male 40200 IU/L

Female 35150 IU/L

CKMB


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LIPOPROTEIN PANEL

This includes the following four

Total Serum Cholesterol. Low Density Lipoproteins. High Density Lipoproteins. Triglycerides.


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1. TOTAL SERUM CHOLESTEROL:

Cholesterol is an important component of cell membranes and is necessary for the synthesis of manyhormones and bile salts. Elevated total serum cholesterol is a useful screening test to determine CoronaryHeart Disease (CHD).

2.LOW DENSITY LIPOPROTEINS: (LDL)

Low density lipoprotein is a major cholesterol transport protein. LDL is considered the bad cholesteroland has been linked to atherogenesis.

Desired Range SI Units Clinical Significance

Desirable Level


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3. HIGH DENSITY LIPOPROTEINS: (HDL)

High density lipoproteins are responsible for transport of 20% to 30% of serum cholesterol. HDLremoves excess cholesterol from peripheral tissues. It is considered the good cholesterol and elevatedHDL levels are associated with a decreased risk for CHD.

4. TRIGLYCERIDES:

Triglycerides are the main storage form of fatty acids.

Blood Levels SI Units Clinical Significance

Normal Range3070 mg/dL

Desired Range>40 mg/dL

SI 0.781.81 mmol/L

SI >1.04 mmol/L

Decreased HDL may be associatedwith cigarette smoking, diabetes

mellitus, lack of exercise and use ofanabolic/androgenic steroids or Beta

blockers.Elevated HDL may be seen with

moderate alcohol intake or in patients

taking estrogens, oral contraceptivesor nicotinic acid.

Blood Levels SI Units Clinical Significance

Normal Range5.64 mmol/L

Triglycerides may be significantlyelevated in the nonfasting state and

should be measured after a fast ofat least 1214 hours.

In addition to lipid disorders,elevated triglycerides may beassociated with a nonfesting

sample, diabetes mellitus,pancreatitis, nephrotic syndrome,chronic renal failure, alcoholism,

gout and use of oral contraceptivesor intravenous lipid infusions.


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ENDOCRINE DIAGNOSTIC TESTS

1. THYROID FUNCTION TESTS

Thyroid stimulating hormone Thyroxin Free thyroxin Total tri-iodothyronine

2. DIABETES MELLITUS

Hemoglobin A 1c

3. ADRENAL GLAND TESTS

Cortisol Dexamethasone suppression test Adrenocorticotropic hormone Adrenocorticotropic hormone stimulation test


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1. THYROID FUNCTION TESTS:

It includes the following four tests

Thyroid stimulating hormone Thyroxin Free thyroxin Total tri-iodothyronine

i) THYROID STIMULATING HORMONE: (TSH)

Thyroid Stimulating Hormone is sensitive screening test used to detect hypothyroidism orhyperthyroidism.

International Units SI Units Elevated Thyroid

Stimulating Hormone

Low Thyroid

Stimulating Hormone

0.35 U/Ml 0.35 mU/L Elevated thyroidstimulating hormone

levels are indicative ofhypothyroidism. TSH

may be falsely elevated

in the first trimester ofpregnancy.

Abnormally low TSHlevels (< 10) are

associated withhyperthyroidism.Medications with

dopaminergic activitycan decrease TSH

levels.Abnormal TSH levels

should be followed upwith the thyroidhormone test (T3 or

T4).TSH should bemonitored 6 to 8 weeks

afer initiation or achange in therapy.


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ii)THYROXINE: (T4)

T4 is the predominant circulating thyroid hormone. T4 levels are a measure of the functional status of thethyroid gland. T4 may also be used to monitor thyroid therapy. T4 levels may be affected by conditionsthat increase or decrease the thyroxin binding proteins.

International Units SI Units Increased T4 Decreased T4

412 g/dL 51154 nmol/L T4 can be increased inhyperthyroidism,

pregnancy, hepatitis andthe use of estrogen

replacement therapy ororal contraceptives.

Decreased T4 is mostcommonly seen in

hypothyroidism butmay also be associated

with renal function,malnutrition, cirrhosis

and use of medications

that compete for T4binding sites on T4

binding proteins.

iii) FREE THYROXINE: (Free T4)

Total T4 levels can be affected by conditions that alter the amount of thyroxin binding proteins, freeT 4 isthe most accurate reflection of clinical thyroid status.

International Units SI Units Increased T4

0.82.7 ng/dL 1035 pmol/L Free T4 is a diagnostic test that may be usedto confirm the diagnosis of hypothyroidism

or hyperthyroidism. Free T4 levels may beincreased or decreased by amiodarone and

iodides and decreased with sulfonamidesand lithium.


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iv) TOTAL TRIIODOTHYRONINE: (T3)

The majority of T3 is formed from de-iodination of T4in the kidney and liver. Total T3 measures bothbound and unbound T3. T3 is usually used in the diagnosis of hyperthyroidism or T3 toxicosis but has littleutility in the diagnosis of hypothyroidism.

International Units SI Units Increased T3 Decreased T3

80160 ng/dL 1.22.5 nmol/LIncreased T3 is seen inhyperthyroidism, T3

toxicosis, high doses oflevothyroxine and other

conditions that alsoincrease T4

Decreased T3 may beassociated with

hypothryodism andmalnutrition.

Glucocorticoids andpropranolol decrease

peripheral conversion

of T4 to T3 and mayresult in reduced T3

levels.


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2. DIABETES MELLITUS:

It includes only the following test

HEMOGLOBIN A1C: (HbA1C)

HbA1C measures the percentage of hemoglobin molecules that are bound to glucose. During the life spanof RBC, glucose binds irreversibly to hemoglobin in the RBC. As the serum glucose becomes more

elevated, more glucose binds to the hemoglobin. Because the RBC has a life span of approximately 120days, the HbA1C reflects blood glucose control for the 2 to 3 months preceding the test.

From the HbA1C, the average blood glucose may be calculated as follows:

Mean Blood Glucose = 33.3 (HbA1C)86


46 %

The HbA1C may be used to assess blood sugar control over the 2 to 3

months preceding the test. An HbA1C greater than 7 % indicates theneed for improved diabetic control through adjustment of diet,

exercise or medication regimen.


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3. ADRENAL GLAND TESTS:

This test includes

Cortisol Dexamethasone suppression test Adrenocorticotropic hormone Adrenocorticotropic hormone stimulation test

i) CORTISOL:

Cortisol is a hormone produced by the adrenal cortex. It plays a critical role in carbohydrate metabolismand response to stress. Cortisol plasma levels undergo a normal diurnal variation and are highest in the

early morning.

International Units SI Units Increased Cortisol Decreased Cortisol

Morning625 g/dL

Evening312 g/dL

165690 nmol/L

83331 nmol/L

Increased cortisol levelsare associated withCushings disease,

Cushings syndrome,hyperthyroidism, oral

contraceptive use,pregnancy, stress and

morbid obesity.

Decreased cortisol maybe secondary to

Addisons disease,hypothyroidism ordecreased pituitary

function.

ii) DEXAMETHASONE SUPPRESSION TEST:

In this test, 1mg of dexamethasone is given at midnight and plasma cortisol levels are drawn at 8:00 a.m.In a normal patient, the administration of exogenous steroid (dexamethasone) should suppress the releaseof cortisol from the adrenal gland. The dexamethasone suppression test is useful in the diagnosis of

Cushings syndrome.


Cortisol5 g/dL suggests the diagnosisof Cushings syndrome. Elevated cortisol levels

may also be seen in patients who are undervarious types of stress, including acute illness,

pregnancy and psychiatric disorders. Resultsshould be interpreted with caution un these

populations.


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iii)ADRENOCORTICOTROPIC HORMONE: (ACTH)

Adrenocorticotropic Hormone is a hormone secreated from the anterior pituitary. It controls the release ofcortisol from the adrenal gland.

International Units SI UnitsIncreased

AdrenocorticotropicHormone

DecreasedAdrenocorticotropic

Hormone

< 60 pg/Ml


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GASTROINTESTINAL / HEPATIC/ PANCREATIC

DIAGNOSTIC TESTS

They include the following important tests

Alanine Aminotransferase Aspartate Aminotransferase Alkaline Phosphate Ammonia Bilirubin Glutamyl Transpeptidase Lactate Dehydrogenase Amylase Lipase Helicobacter pylori IgG Hemoccult


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1. ALANINE AMINOTRANSFERASE: (ALT)

Formerly called as Serum Glutamic Pyruvic Transaminase (SGPT)

ALT is an intracellular enzyme present in liver tissues. It is also located in myocardial muscle and renal

tissues.

Normal Range SI Units Clinical Significance

035 U/L 00.58 kat/L

(varies with assay)

High serum ALT concentrations are indicative of

hepatocellular disease. Elevations greater than two times theupper limit of normal are considered significant.

ALT is much more concentrated in liver tissue than theaminotransferase AST and is considered more specific

marker for liver disease.

Increased levels of ALT may occur with hepatitis, alcoholic

liver disease, CHF, mononucleosis and cholestasis. ElevatedALT may be caused by a number of medications including

HMG-CoA reductase inhibitors and niacin.

2. ASPARTATE AMINOTRANSFERASE: (AST)

Formerly called as Serum Glutamic Oxolacetic Transaminase (SGOT)

AST is another intracellular aminotransferase found in the liver. It is also present in the heart, kidney,pancreas, lungs and skeletal muscle. Injury to these tissues will release AST into the systemic circulationand result in serum AST elevation.


040 U/L 00.67 kat/L(varies with assay)

Elevated AST is associated with hepatitis, alcoholicliver disease, cholestasis, pericarditis, acute

myocardial infarction, trauma, CHF, mononucleosis,severe burns, renal infarction, pulmonary infarction,

pulmonary embolus and acute pancreatitis.In alcoholic liver disease, the ratio of AST to ALT isusually greater than 2:1.

Elevations of AST may also be seen with drugtoxicity. Erythromycin, Levodopa, Methyl dopa andTolbutamide may falsely elevate AST by interfering

with the assay.


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3. ALKALINE PHOSPHATE: (Alk Phos)

Alkaline Phosphatases are a group of isoenzymes located in bones, liver, intestine and the placenta.

Normal range Clinical significance

This varies with age and assay

used.

Elevated concentrations of alkaline phosphatase may be seen in a

variety of conditions including obstructive liver disease, cholestasis,and cirrhosis, healing bone fractures, Pagets disease, bone

metastases, hyperthyroidism, pregnancy and sepsis.

If the source of elevated alkaline phosphatase is unclear theisoenzyme may be fractionated to discern if the cause is liver, bone

or other. Alternatively, an increased glutamyl transpeptidase(GGT) with an elevated alkaline phosphatase is highly suggestive of

a live source for the increased alkaline phosphatase.

4. AMMONIA: (NH3)

Ammonia is generated through metabolism of protein by intestinal bacteria. Usually ammonia is absorbed

into the systemic circulation, metabolized by the liver and the by-product urea is excreted by the kidneys.Ammonia concentration is most often used in the diagnosis and monitoring of hepatic encephalopathy.


3070 g/dL 1741 mol/L Elevated concentrations of ammonia areassociated with cirrhosis, other liver diseases,

Reyes syndrome and inherited disorders of theurea cycle.


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5. BILIRUBIN: (Bili)

Bilirubin is a breakdown product of hemoglobin. The bilirubin produced from hemoglobin metabolism is

referred to as unconjugated or indirect bilirubin. Unconjugated bilirubin is converted to conjugated ordirect bilirubin by the liver through the process of glucuronidation. Conjugated bilirubin is excreted into

the bile and subsequently into the intestine. In the intestine, some bilirubin is excreted in the feces and theremainder is broken down to urobilinogen. Urobilinogen is later excreted renally.


Total Bili

0.11.0 mg/Dl

Indirect

0.20.7 mg/Dl

Direct00.2 mg/Dl

218 mol/L

3.412 mol/L

03.4 mol/L

Increased levels of indirect bilirubin may

result from hemolysis, large hematomas andthe inherited disorder Gilberts syndrome.Elevated direct bilirubin may be associated

with hepatpcellular disease, hepatitis,cirrhosis and cholestasis. Jaundice is a

classic sign of hyperbilirubinemia thatusually occurs when total bilirubin exceeds

24 mg/dL.

6. GLUTAMYL TRANSPEPTIDASE: (GGT, GGTP)

Glutamyl transpeptidase is an enzyme found in the liver, kidney and prostate. GGT levels are useful in

the diagnosis and monitoring of alcoholic liver disease

Normal Range SI Units Clinical Significance:

Male 065 U/L

Female 040 U/L

0.11.08 kat/L

00.67 kat/L

Increased GGT activity may be seen in

alcoholic liver disease, metastatic liverdisease, obstructive jaundice, cholelithiasis,

pancreatitis, myocardial infarction and CHF.Enzyme inducers that cause microsomal

proliferation such as Phenobarbital,rifampicin, phenytoin and carbamazepine

may also increase GGT levels.


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7. LACTATE DEHYDROGENASE: (LDH)

Lactate dehydrogenase is an enzyme involved in the interconversion of lactate and pyruvate. It is found inmany tissues, including heart, brain, liver, skeletal muscle, kidneys and RBCs.


100210 IU/L 1.673.5kat/L

Elevated levels of LDH5 are indicative of liver disease and may beseen in hepatitis, cirrhosis and biliary tract obstruction. LDH1 and

LDH2 may be used to confirm the diagnosis of myocardial infarction.Other conditions associated with increased LDH include hemolysis,

trauma, muscular dystrophy, pulmonary embolism, pulmonary

infarction, acute renal infarction, malignancy and myocarditis.

8. AMYLASE:

Amylase is an enzyme that aids digestion by breaking down starch into glucose. The majority of amylaseoriginates from the pancreas and salivary glands and lesser amounts are secreated by the fallopian tubes,lungs, thyroid and tonsils.


20128 IU/L

Increased concentrations of amylase may be seen in acute

pancreatitis, exacerbationof chronic pancreatitis, cholecystitis,appendix, ruptured ectopic pregnancy, mumps, alcoholism and

diabetic ketoacidosis.


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9. LIPASE:

Lipase is an enzyme that aids in the digestion of fat. Lipase is primarily secreted by the pancreas and isuseful in the diagnosis of pancreatitis. The lipase level begins to rise within 2 to 6 hours of onset of acute

pancreatitis.


< 15 U/Dl Elevations of lipase are associated with pancreatitis. It may also be elevated withcholecystitis, cirrhosis, pancreatic cancer and small bowel obstruction.

If lipase is normal and amylase is elevated this suggests a non pancreatic origin forthe increased amylase.

10. Heli cobacter pylori I gG:

It is a curved gram negative rod that is responsible for the majority of cases of peptic ulcer disease .

H.pylori can be detected in 90% to 100% of patients with duodenal ulcers and 70% to 80% of patientswith gastric ulcers.

Normal Value Clinical Significance

Negative

A positiveH.pylori IgG in presence of dyspeptic symptoms is highly suggestiveof peptic ulcer disease and a course of antibiotic therapy is warranted.H.pylori

IgG may remain positive for many months after treatment of the infection.

11. HEMOCCULT:

It is most commonly used to detect the presence of occult blood in the stool.


Negative A positive hemoccult test indicates blood loss in the GIT.A false positive result may be obtained if the patient is receiving iron

supplementation or has eaten red meat, broccoli, turnips or radish within 3 daysof the test. False negatives may occur in patients taking high doses of vitamin C.


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HEMATOLOGIC DIAGNOSTIC TESTS

It includes the following

Iron Ferritin Total Iron Binding Capacity (TIBC) Vitamin B12 (Cyanocobalamin) Folate


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1. IRON:

Serum iron measures the concentration of iron bound to the iron transport protein transferring.Approximately one third of transferring molecules are bound to iron.

Normal Range SI Units Increased Serum Iron Decreased Serum Iron

Male50160 g/dL

Female

40150 g/dL

929mol/L

727mol/L

Increased iron may beassociated with excessive

iron therapy, frequenttransfusions, pernicious

anemia, hemolytic

anemia, thalassemia andhemochromatosis (iron

overload).

Reduced serum iron is mostcommonly associated with iron

deficiency anemias. Causes includepoor dietary intake, pregnancy,

blood loss associated with menses,

peptic ulcer, gastrointestinalbleeding and inflammatory bowel

disease.

Other causes of decreased iron aremalignancies, anemia of chronic

disease, chronic renal disease,hemodialysis and some infections.

2. FERRITIN:

Ferritin is the storage form of iron. The serum ferritin level provides an accurate reflection of total bloodcapacity.

Normal Range Increased Serum Ferritin Decreased Serum Ferritin

Male15200 ng/mL

Female

12150 ng/ mL

Increased ferritin may result fromhemochromatosis, mligancies,

inflammation, acute hepatitis andliver disease.

Decreased serum ferritin isassociated with iron deficiency

anemia.


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3. TOTAL IRON BINDING CAPACITY: (TIBC)

It is an indirect measurement of serum transferring. The test is performed by adding an excess of iron to aplasma sample. Any excess unbound iron is removed from the sample and serum iron concentration in thesample is measured.

Normal Range SI Units Increased TIBC Decreased TIBC

250400

g/dL

44.871.6

mol/L

Increased TIBC may be

associated with irondeficiency anemia,

pregnancy and oralcontraceptive use.

Decreased TIBC may be caused

by anemia of chronic disease,malignancy, infections, uremia

and hemochromtosis.

4. VITAMIN B12 : (Cyanocobalamin)

This test measures serum levels of vitamin B12. Vitamin B12 is important in DNA synthesis, neurologicalfunction and malnutrition of RBCs. Deficiency of vitamin B12 produces macrocytic anemia.

Patients may also present with glossitis, paresthesias, muscle weakness, gastrointestinal symptoms, lossof coordination, tremors and irritability.


10090 pg/mL 74664 pmol/L Decreased vitamin B12 may be caused by inadequatedietary intake, decreased production of intrinstic

factor or decreased absorption of B12. Decreasedlevels of B12 are associated with pernicious anemia,

gastrectomy, Chrons disease, small bowel resection,intestinal infections and use of colchicines or

neomycin.


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5. FOLATE:

This test measures serum folate and is necessary for the synthesis of DNA. Deficiency of folic acid resultsin a megaloblastic anemia.


3.112.4ng/mL

7.028.1nmol/L

Inadequate intake, decreased absorption or inability to convert folic

acid to the active form tetrahydrofolic acid may cause decreased folicacid levels.

Folate deficiency is associated with alcoholism, poor nutrition,

pregnancy, hyperthyroidism, Crohns disease, small bowel resection,celiac disease and use of medications such as trimethoprim,

sulfamethoxazole, methotrexate and sulfasalazine.


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COAGULATION TESTS

It includes the following:

Prothrombin time (PT) Activated partial thromboplastin time International normalized ratio (INR)


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1. PROTHROMBIN TIME:

The prothrombin test is sensitive to changes in the levels of clotting factors prothrombin (factor II), factor

(VII) and factor (X). it is performed by adding thromboplastin and calcium to a plasma sample. After

addition of these reagents, the time it takes the blood to clot is measured.

Normal range Clinical significance

1113 seconds (varies) The PT is used to monitor warfarin therapy. PTmay vary according to the thromboplastin used to

test the sample, the international normalized ratio isa better monitoring tool.

The normal PT in a person not on anticoagulationtherapy is 1113 sec. an increase in PT may be

see with anticoagulation therapy, liver diasease,vitamin K deficiency and clotting factor

deficiencies.

2.ACTIVATED PARTIAL THROMBOPLASTIN TIME :(aPTT)

The aPPT is sensitive to changes in the clotting factors thrombin (factor IIa), factor (Xa) and factor (IXa).It is used to monitor heparin therapy.


2045 seconds (varies) The normal value represents a control range forpatients not on anticoagulation therapy. Patients on

heparin therapy will have an elevated aPTT.Muchlike the prothrombin time; the aPTT can vary

depending on the reagent (partial thromboplastin)used to test the sample.


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3. INTERNATIONAL NORMALIZED RATIO :(INR)

PT may vary due to the thromboplastin used, the INR is used to standardize the PT. the INR adjusts the

PT ratio based on the sensitivity of the thromboplastin used to perform the test.

INR = [(patient PT) / (mean normal PT)]ISI

ISI is the international sensitivity index rating assigned to a particular thromboplastin.

Desired ranges for the INR are as follows.

INR 2.03.0Atrial fibrillation

DVT treatmentPE treatment

Prophylaxis of venous thrombosisTissue heart valvesValvular heart disease

INR 2.53.5Mechanical prosthetic valve

Desired Range Clinical Significance

Depends on indication for anti coagulation INR below range indicates suboptimal anti

coagulation and a need to increase warfarin dosge.An INR above the deired range indicates a need to

reduce the warfarin dosage.Patient should be questioned regarding dosage of

warfarin, missed doses, dietary intake and

concomitant medications.


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IMMUNOLOGICAL DIAGNOSTIC TESTS

This includes the following:

Anti nuclear anti bodies (ANA Titer) Rheumatoid factor (RF) Erythrocyte sedimentation rate (ESR)


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1.ANTI NUCLEAR ANTI BODIES :(ANA Titer)

Antinuclear antibodies (ANA Titer) are antibodies directed against nucleic acids and other nucleicproteins. The ANA test is used as a diagnostic tool for autoimmune and connective tissue diseases,

particularly systemic lupus erythematosus (SLE).


< 1:20 or < 1:40(varies)

High titers may be associated with SLE, rheumatoid arthritis, scleroderma,Sjogens symdrome, polymyositis, dermatomyositis and drug induced lupus

(hydralazine, procanamide).False positive ANA test may occur in 25 % of healthy patients. Falsepositive results may be caused by use of certain medications, including

Carbamazepine, Chloropromazine, Methyldopa and Phenytoin.

2.RHEUMATOID FACTOR: (RF)

Rheumatoid factor is an immunoglobulin whose activity is directed against IgG. Thus, a positive FR test

(titer 1:160 or greater) is indicative of an autoimmune process.


< 1 : 160 A positive rheumatoid factor test is most commonly associated with rheumatoidarthritis but may also be seen with SLE, scleroderma, Sjogrens syndrome,

malignancy and infectious diseases such as tuberculosis, syphilis and

endocarditis.

3. ERYTHROCYTE SEDIMENTATION RATE: (ESR)

ESR measures the rate of erythrocyte settlement in anticoagulated blood. In the presence of proteinsknown as acute phase reactants, erythrocytes settle much more quickly. Acute phase reactants are oftenassociated with infectious or inflammatory disorders. ESR is a nonspecific diagnostic test that may be

used to support a diagnosis or monitor the progress of an inflammatory or infectious process.


Male 115 mm/hr (increases with age)

Female 120 mm/hr (increases withage)

The ESR may be elevated in infections such as tuberculosis

and syphilis, maliganancies, ulcerative colitis, polymyalgaiarheumatic, temporal arteritis, rheumatoid arthritis, SLE,

scleroderma and other collagen vascular disease.


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INFECTIOUS DISEASE DIAGNOSTIC TESTS

Following tests are included in this section

ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA) for HIV WESTERN BLOT CD4 (T4 LYMPHOCYTES) HIV VIRAL LOAD RAPID PLASMA REAGIN (RPR) VENEREAL DISEASE RESEARCH LABORATORY TEST (VDRL)


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1. ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA) for HIV:

The ELISA test for HIV detects anti bodies to HIV. It is a highly sensitive and specific testand is mostcommonly used for screening test for HIV.

False Positive False Negative

False positive results may occur in patients withlupus, syphilis, influenza, hepatitis B vaccine,

chronic hepatitis and malaria. Positive tests shouldbe repeated to assure positive results. Repeatedly

positive samples should be confirmed with thewestern blot test.

False negative results may be seen in early HIVinfections, malignancy nd bone marrow transplant.

2. WESTERN BLOT:

It is a confirmatory test used following a positive ELISA result. It detects antibodies to specific HIVproteins and glycoprotein.

Positive Result False Negative / Indeterminate

A positive result following a positive ELISA test

confirms the diagnosis of HIV.

False negative or indeterminate results may occur if

seroconversion is not complete. Individuals shouldbe retested at a later date.


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3. T4 LYMPHOCYTES: (CD4)

CD4 cells are a subset of lymphocytes also known as helper cells. CD4 cells are responsible for cellmediated immunity and are good marker of immune function.


4001185/mm3 As the CD4 cell count decreases, the patient is at increased riskof acquiring opportunistic infections. When the absolute CD4

cell count falls to less than 200, the diagnosis is no longer justHIV but AIDS.CD4 cell counts are used as an indicator for

starting prophylaxis in HIV patients (e.g., PCP prophylaxis isinitiated at a CD4


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5. RAPID PLASMA REAGIN (RPR):

RPR is a non treponemal serological test used to screen for syphilis. It may also be used to assessresponse to syphilis therapy.

Normal Value False Positive False Negative

Non reactive It may occur with other infectiousdiseases such as measles, chickenpox,

malaria, mononucleosis, hepatitis,early HIV infections and conditions

such as pregnancy, lupus andconnective tissue disease.

They may be seen early in infection andin late infection the test may also be non

reactive.A fourfold decline in the RPR titer after

1 year may also be considered anadequate response to treatment.

6. VENERAL DISEASE RESEARCH LABORATORY TEST:(VDRL)

The VDRL is a nontreponemal serologic test to screen for syphilis. It may also be used to assess responseto syphilis therapy.

Normal Value False Positive False Negative

Non reactive May be caused by infectiousdiseases such as measles,

chickenpox, malaria,

mononucleosis, hepatitis, earlyHIV infections and other

conditions such as pregnancy,lupus and connective tissue

disease.

False negative results may be seen inearly infection and in late infection the

test may also be nonreactive

Most patients revert to a non reactive testfollowing successful treatment. A

fourfold decline in the VDRL titer after 1year may also be considered an adequate

response to treatment.


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HEPATITIS A

This includes the following two

Anti HAV IgM Anti HAV IgG


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1. ANTI - HAV IgM:

Hepatitis A IgM antibodies may be detected in the serum 4 6 weeks after exposure to hepatitis A andoften coincide with the onset of jaundice.


Negative The presence of anti HAV IgM indicates acutehepatitis A 2, 5.22. Anti HAV IgM becomes negative

within 23 months after acute hepatitis.

2.ANTI - HAV IgG:

Anti- HAV IgG can be detected 612 weeks after exposure to Hepatitis A.


Negative Presence of anti HAV IgG indicates previousinfection with HAV and immunity to the virus 2,

22, 32.


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HEPATITIS B

This includes the following

Hepatitis B Surface Antigen (HBsAg) Hepatitis B e Antigen (HBeAg) Hepatitis B Core Antibody (antiHBc) Hepatitis B Surface (antiHBs)


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1. HEPATITIS B SURFACE ANTIGEN: (HBsAg)

HBsAg is a protein coat that surrounds the hepatitis B virus. It can be detected in the serum 412 weeksafter infection.


Negative A positive test for HBsAg indicates acute hepatitis B. persistence of HBsAg for20 weeks or more after acute infection is indicative of chronic hepatitis B.

2. HEPATITIS B e ANTIGEN: (HBeAg)

HBeAg is used to assess the degree of infectivity of patients with hepatitis B.

Normal value Clinical significance

Negative Presence of HBeAg is associated with active viral replication and a high degreeif infectivity. HBeAg is usully present for 26 weeks after acute infection.

Persistence of HBeAg is indicative of chronic hepatitis.

3. HEPATITIS B CORE ANTIBODY: (ANTIHBc)

AntiHBc may be detected in the blood a few weeks after the appearance of HBsAg.


Negative Positive results for anti HBc indicate past infection with hepatitis B. theseantibodies seem to persist for life.


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4. HEPATITIS B SURFACE ANTIBODY: (ANTIHBs)

AntiHBs is usually detected in the blood 56 months after infection.


Negative Presence of antiHBs indicates recovery and immunity to hepatitis BIndividuals who been vaccinated for hepatitis B will test positive for antiHBs.Because antiHBs levels may decline or disappear over time, revaccination at 5

7 years is recommended.


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HEPATITIS C ANTIBODY: (ANTI HCV)

Anti HCV is used as a screening test for hepatitis C virus.


Negative Presence of anti HCV indicates prior exposure to or

chronic infection with hepatitis C. unlike antibodiesto hepatitis A and hepatitis B, antibodies to

hepatitis C do not confer immunity.Antibodies may not be present until 6 - 12 weeks

after acute infection.

A positive test for anti HCV should be followed bya confirmatory test such as radioimmunoblot assay

(RIBA) or hepatitis C viral load (HCV RNA byPCR).22,34

laboratory data(1)l

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