Download LabdxIImidterm

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Lab. DI. II / MID-TERM REVIEW / DR. SANDERS
READING FROM “LAB. DIAGNOSTIC TESTS” = FISHBACH
June 96 (Retyped March ‘ 97)
FASTING BLOOD GLUCOSE (FBG): Normal (65-110)
Glucose is formed from carbohydrate digestion & conversion of glycogen to glucose by the liver.
The two hormones, Glucagon & Insulin, directly regulate blood glucose. As metabolism occurs, blood glucose
levels fall
Glucagon: Accelerates glycogen breakdown in the liver & causes blood glucose to rise.
Insulin: Increases cell permeability to glucose, transports glucose into the cells for metabolism, stimulates
glycogen formation, & reduces blood sugar levels.
The Islets of Langerhan, the Endocrine portion of the Pancreas, are the sources of both Insulin & Glucagon.
Fasting Glucose is a vital component of diabetes management. Usually an elevated level (> 140 mg/dl =
HYPERGLYCEMIA) is diagnostic for diabetes, although borderline patients may present with normal fasting
values.
A glucose tolerance test can confirm a diagnosis of diabetes. Other diseases can produce elevated glucose
(sugar) levels.
ALKALINE PHOSPHATASE (ALP):
An enzyme originating mainly in the bone, liver, placenta, with some activity in the kidney & intestines.(Follow
canned notes P.29)
TWO - HOUR POSTPRANDIAL BLOOD SUGAR (2-HR. PPBS);
(Glucose) in a 2 hour fasting blood specimen after a meal is rarely elevated in non-diabetics adult; but is
increased in diabetics.
GLYCOSOLAED HEMOGLOBIN (HbA 1c):
Results are expressed as (%) of total hemoglobin.
In a normal (non-diabetic adult = (5.5 - 8.5%)
The test reflects average blood sugar levels for the (2-3) month period before the test. It provides information
for evaluating diabetic treatment modalities, especially in diabetic children, uncontrolled or poorly controlled
diabetes mellitus. Used to monitor long term glucose control.
BILIRUBIN (total adult bilirubin): Normal (0.2-1.0mg/dl)
Bilirubin results from the breakdown of hemoglobin in RBC’s. It is removed from the body by the liver.
Gives bile its pigmentation (color)
The measures of bilirubin evaluate Liver Function, Hemolytic Anemias, and Hyperbilirubinemia (in Newborns).
(p. 32 in can)
B.U.N. (Blood Urea Nitrogen): Normal (7-18 mg/dl)
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Urea forms in the liver & along with co2 constitutes the final by product of protein metabolism. Urea levels
vary directly with protein intake, with increased excretion with fever, diabetes, and increased adrenal gland
activity.
Test is a gross indicator of glomerular function. The rise in the BUN is influenced by the degree of tissue
necrosis, protein catabolism & the rate of Urea Nitrogen Excretion from the kidneys.
CREATININE: Normal (0.6-1.3 mg/dl):
Creatinine is a by product of the breakdown of muscle cratinine phosphate, resulting from energy metabolism.
It is produced at a constant rate (as long as the muscle mass remains constant), Depending on the muscle mass
of the individual & is removed from the body by the kidneys.
Creatinine excretion is decreased with kidney disorders, resulting in increased levels in the blood.
A more specific & sensitive test for renal function than BUN.
URIC ACID: Normal (3.5 - 7.2 mg/dl)
An end product of Purine metabolism. (2/3) is excreted by the kidneys; (1/3) by the stool.
Over production of uric acid occurs with excessive cell breakdown, or an inability to excrete the substance
produced.
CREATININ (PHOSPHO) KINASE (CK) & ISOENZYMES:
Is an enzyme found in the heart, skeletal muscle, & brain. Used as a specific index of myocardial infarction,
muscle injury, & disease.
LACTIC DEHYDROGENASE (LDH) & IOENZYMES:
Is an intercellular enzyme, widely distributed in the tissues of the body. Increases indicate cell leakage.
ASPARTATE AMINOTRANSFERASE (AST) :
An enzyme present I tissues of high metabolic activity.
Amount rises directly with cell injury or death & the time that has passed after the injury & before the test.
Severe injury = AST rises in 12 hours & is high for 5 days.
ALANINE TRANSAMINASE (ALT)
Used primarily to diagnose liver disease. Differs between Hemolytic Jaundice & that caused by Liver Disease.
CALCIUM: Normal (8.6-10.0 mg/dl)
(98-99%) Is stored in bones & teeth
Amount of protein in the blood affects calcium levels cause (50%) of the blood calcium is protein bound.
PHOSPHROUS: Normal (2.5-4.5 mg/dl)
(85%) of Phosphorous is combined with calcium in the bone;
The rest is with in the cells.
It enters the cell with glucose & is lowered after carbohydrate ingestion.
Levels are always evaluated in relation to calcium because there is an inverse relation between the two. An
excess in one of these electrolytes causes the kidneys to excrete the other. As with calcium, the controlling
factor is parathyroid hormone.
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MAGNESIUM: Normal (1.3-2.1 mEq/L):
Is concentrated in bone, Cartilage, & cells themselves & is needed for the use of ATP as an energy source.
Regulates neuromuscular irritability & clotting mechanisms. Measures are an index of metabolic activity &
used to evaluate renal function & electrolyte status.
SODIUM: Normal (135-145 mmol / L):
Sodium is the most abundant cation (90% of the electrolyte fluid) & the chief base of blood.
Its primary function is to chemically maintain the osmotic pressure, acid - base balance, & transmit nerve
impulses. Test detects gross changes in water & salt balance.
POTASSIUM: Normal (3.5-5.3 mmol/L)
Is the main electrolyte of intercellular fluid & primary buffer with in the cell itself.
(90% is with in the cells).
Damaged cells release potassium into the blood. Important for nerve conduction, muscle function, acid base
balance, & osmotic pressure. Helps control cardiac output
(force contraction).
Chloride: Normal (98-113 mmol/L)
Maintains cellular integrity.
A blood electrolyte & anion which exist as a combination in NaCl & HCl acid.
LAB TEST INFORMATION
(ALP)
Used as a tumor marker
Found in bone, Liver & Placenta An index of bone & liver disease
Normal Values = Established in healthy, young population.
Calculations include (2 standard deviations from the mean (average) and accounts for 95% 0f the population;
also accepted as the normal confidence interval of tests.
Only 5% of the population is not included in the normal value.
Greater than 10% difference B/L in ROM is considered a Primary Disability.
Test must be judged in reference to a specific age & population.
Normal ranges are dependent upon 
Population Demographics
Environment
Analytical Method Used
A wide range of causes for a test will restrict its utility. E.g. = its specific for nothing or general for many things.
Cystic Fibrosis “Sweat Test” Is about as perfect a test as there is today. There are no perfect tests.
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A test result W.N.L. = Doesn’t indicate the absence of disease. A test result outside the normal limits doesn’t
necessarily indicate the presence of disease.
Decision Critera: Arevalues of a measured quantity which enable you to distinguishdisease from a reference
population w/o the disease.
(4) Teat Criteria 
Valid (Tests what it says it tests)
Reliable (Repeatedly test well)
Sensitive (+’s in diseasedpop.)
Specific ( -‘s in disese free pop.)
3 & 4 are mutually exclusive of one another
The performance of a test differs with each given population. Tests are relative only within the tome
framethey were taken.
Predictive value: Defines the (%) of posotivesor negative results that are TRUE positives and Negatives.
SERUM is taken from clotted samples; PLASMA from anticoaggulated samples.
LAB TESTS NORMAL LEVELS QUIZ
Write the normal levels for each element given.
1. Sodium___________
2. Chloride__________
3. Glucose___________
4. BUN_____________
5. Calcium___________
6. Uric Acid__________
7. Potassium_________
8. Phosphorous_______
9. Magnesium________
10. Creatinine_________
11. Bilirubin__________