Organ Function Test

Front 1

Define Organ Function Test

Back 1

• Collection of individual test used to evaluate organ functionality
• Useful to detect the presence of disease, monitoring response to treatment, evaluating prognosis

Front 2

Describe the shotgun approach.

Back 2

Numerous function tests are utilized → confuses investigation
o Better to perform simple testes

Front 3

Define screening.

Back 3

extremely sensitive and should detect all treatable disease (true positive)

Front 4

Define sensitivity.

Back 4

probability that true positives are detected

Front 5

Define Specificity.

Back 5

probability that a organ function test returns negative results if person does not have the disease

Front 6

Describe the purpose of a Kidney Function Test.

Back 6

• glomerular filtration rate = important index of glomerular function (declines with renal disease)
• renal failure = acute rapid decline or gradual insidious decline
• dysfunction is a result of accum. of metabolic waste products
• kidney function test evaluate kidney function (particularly in diabetics or anti-gout therapy)

Front 7

Define Plasma creatinine. (Blood)

Back 7

• Originates from endogenous muscle turnover
• Assays enables the progress of renal disease (increases w/ progression)
• More specific than BUN
• Men: 0.8-1.2 mg/dL
• Women: 0.6-0.9 mg/dL

Elevated in;
impaired kidney function (fall in GFR)
salicylates & cimetidine

Reduced in;
during pregnancy
children

Front 8

Define Blood Urea Nitrogen.

Back 8

• Urea is produced in the liver
• Waste product
• BUN quickly, accurately and precisely measures nitrogen in urea
• Recently used to predict mortality of acute pancreatitis
• Range = 7-20 mg/dL

Elevated in;
Kidney dysfunction

Reduced in;
lack of protein
severe liver disease
dehydration
during pregnancy
children

Front 9

Define Creatinine clearance test.

Back 9

• Measures efficacy with which the kidneys clear creatinine from blood
• Very specific but NOT an ideal glomerular filtration rate
• men <40; 90-139 ml/min men
• women <40; 80-125 ml/min
• adults >40; decrease by 6.5 ml for each decade

Front 10

Define Urea clearance test.

Back 10

• Requires both blood & urine samples
• Collected 1hr apart to estimate amount of urea filtered
• No longer used since its dependent on urine flow and does not reflect glomerulus filteration rate

Front 11

Define Urine Protein test.

Back 11

• Kidneys filters appx. 30 mg/L of protein from bloodstream
• Only small amount appears in urine due to tubular reabsorption
o Detected w/ dipsticks (color change of tetrabromophenol, buffered at 3pH) yellow → blue
o Should contain no more than 150 mg

Reduced in;
• Impaired in diabetics

Front 12

Describe the purpose of a Liver Function Test.

Back 12

Synthetic capacity
o Prothrombin Time; measures time taken to form blood clot
o Blood albumin; indicates synthetic deficiency and chronic liver disease

Excretory function
o Plasma assay of bilirubin (most common test)
• Other liver function – plasma enzyme

Front 13

Describe test precautions; discontinue factors that increase.

Back 13

o blood total bilirubin; Drugs- anabolic steroids, diuretics and OC
o Ammonia; alcohol and barbiturates, muscular exertions, cigarette smoke
o ALT; acetaminophen, verapamil, ampicillin
o GGT; phenytoin, alcohol and phenobarbital

Front 14

Define Bilirubin.

Back 14

• Bile pigment bilirubin circulation comes form breakdown of Hb (spleen)
• Normal; below 1 mg/dL
• jaundice; excess bilirubin (>2.5 mg/dL) yellowing body tissue

elevated indirect (unconj.)
o liver dysfunction – hepatitis
o impairment of cell membrane function

elevated direct (conj.)
o intrahepatic blockage of biliary tree
o obstruction of bile flow – tumor or gallstones
o lead increase levels in urine

Front 15

Define Van Den Bergh Diazo Reaction.

Back 15

the direct (conjugate) and indirect (unconjugated) test but both are not performed on same sample

• 1st determine total bilirubin (severity of liver damage)
• 2nd direct van den bergh (estimate of conjugate bilirubin levels)
• estimated unconj. bilirubin is obtained by conj.-total

Front 16

Define Ammonia.

Back 16

• Used to diagnosis and monitor chronic liver problems
• Problems = errors with reliability
• Patients should not smoke and EDTA or heparin should be added to prevent contamination from airborne ammonia
• Relate poorly with other measures of acute hepatic malfunction
• Values vary widely depending on lab, age and type of specimen

Front 17

Describe the purpose of a Cardiac Function Test.

Back 17

• several protein circulate after heart cells are damage
• specific sensitive biomarker present 1-2hrs. after cardiac muscle injury
• creatine kinase assay ( CK-MB) = most commonly used

Front 18

Define Troponin T and I and it's results.

Back 18

• Greater sensitivity & specificity than CK-MB (but both are used)
• Troponin T (cTNT) and troponin I (cTNI) not found in healthy ppl

• Recently troponin L maybe detected even earlier than T & I
o cTNT & cTNI  4-6hrs. following MI
o cTNT & cTNI peak 12-16hrs (levels remain elevated 5-10 days)

• troponin I is frequently assayed by immunoassays and useful in evaluating patient risk following chest pain)
o assayed 6-9hrs. and again at 12-24 hrs if samples are negative

Front 19

Define C-reactive protein and it's results.

Back 19

• Useful marker of chronic inflammation & tissue necrosis produced by the cells of the liver

Elevated
o Following MI and unstable angina
o Atherosclerosis (also measure homocysteine)
• Following MI or cardiac surgery elevated CRP are indicative of further cardiac events & poor prognosis
• Excess of 3 mg/L → elevated risk within 6 years

Front 20

Define Myoglobin and it's results.

Back 20

• Found in striated muscle, damage skeletal or cardiac
• Increased levels in urine (small and does not bind haptoglobulin)
• Screen for early detection of MI

o Rise within 2hrs of heart attack
o Peak with 6-8 hrs
o Levels return to normal 20-36hrs
Also rise in renal failure, therefore when used to diagnosis MI should be combined with CK-MB or cTNT