Kidney function tests

Question 1

1. The plasma concentration of creatinine is maintained
   within narrow limits predominantly by:
   a. the constant catabolism of purines.
   b. the constant rate of protein metabolism.
   c. the glomerular filtration rate.
   d. an individual’s diet.

Answer 1

c. the glomerular filtration rate.

Question 2

2. Symptoms of gout are caused by:

a. decreased renal perfusion as in heart failure.
b. precipitation of excessive uric acid in joints and the
urinary tract.
c. a low-protein diet.
d. liver dysfunction as in hepatitis

Answer 2

b. precipitation of excessive uric acid in joints and the
urinary tract.

Question 3

3. The main nitrogen-containing compound that accounts for more than 75% of excreted nonprotein nitrogen is:

a. uric acid.
b. creatinine.
c. creatine.
d. urea

Answer 3

d. urea

Question 4

4. A deficiency of the enzyme xanthine oxidase due to
   severe hepatocellular disease will lead to:

a. increased urea concentration.
b. decreased creatinine concentration.
c. hypouricemia.
d. hyperuricemia.

Answer 4

c. hypouricemia.

Question 5

5. During protein breakdown, the amino acid nitrogen groups
   are converted to urea through the urea cycle in which of the
   following?

a. Liver
b. Kidneys
c. Heart
d. GI tract

Answer 5

a. Liver

Question 6

6. Compensated Jaffe assays for creatinine assessment:

a. add a fixed value to the assay result to compensate for
interferants.
b. subtract a fixed value from each result to compensate
for noncreatinine interference.
c. use a special formula that involves body mass and
urine production to “normalize” creatinine results.
d. involve averaging of values to remove possible discrepancies between two samples obtained at different
times of the day.

Answer 6

b. subtract a fixed value from each result to compensate
for noncreatinine interference.

Question 7

7. A value of 8.4 mg/dL of urea converts to what in mmol/L?

a. 2.99
b. 29.9
c. 3.92
d. 39.2

Answer 7

a. 2.99

Question 8

8. Ascorbic acid and bilirubin are interferants in which of
   the following assays?
   a. Jaffe reaction and uricase methods
   b. Jaffe reaction only
   c. Jaffe reaction, urease methods, and uricase methods
   d. Urease methods only

Answer 8

a. Jaffe reaction and uricase methods

Question 9

9. In the uricase method of uric acid measurement, the
   main interferants that must be minimized are:

a. phenol and bilirubin.
b. ascorbic acid and bilirubin.
c. endogenous ammonia and oxidizing agents.
d. ketone bodies and protein.

Answer 9

b. ascorbic acid and bilirubin.

Question 10

10. Uric acid is:
    a. the major product of protein catabolism.
    b. a derivative of muscle creatine.
    c. a metabolite of urinary nitrogen.
    d. the major product of purine catabolism

Answer 10

d. the major product of purine catabolism