Renal Function

Question 1

Calculate creatinine clearance, given the following information: serum
creatinine, 1.2 mg/dL; urine creatinine, 120 mg/dL; urine volume, 1,750
mL/24 h; body surface area, 1.80 m2
.

Answer 1

117 mL/min

Question 2

Predict GFR in a 50-year-old woman who weighs 60 kg using the CockcroftGault equation. Her serum creatinine level is 2.5 mg/dL.

Answer 2

2.26 mL/min

Question 3

The measurement of serum cystatin C, a small protein produced by nucleated
cells, is useful for
a. Detecting an early decrease in kidney function
b. Calculating creatinine clearance
c. Diagnosing end-stage renal disease
d. Monitoring dialysis patients

Answer 3

Detecting an early decrease in kidney function

Question 4

Acute renal failure can be classified into three types. List each type and give
an example of each.
a. _______
b. _______
c. _______

Answer 4

a. Prerenal Dehydration (example: severe vomiting or diarrhea leading to reduced blood flow to the kidneys)

b. Intrinsic: Acute tubular necrosis (example: damage to the kidney tubules due to toxins or ischemia

c. Postrenal: Urinary tract obstruction (example: kidney stones blocking the flow of urine)

Question 5

The proximal tubule functions to
a. Reabsorb 75% of salt and water
b. Concentrate salts
c. Form the renal threshold
d. Reabsorb urea

Answer 5

a. Reabsorb 75% of salt and water

Question 6

Renal clearance is the
a. Volume of plasma from which a substance is removed per unit of time
b. Volume of urine produced per day
c. Amount of creatinine in urine
d. Urine concentration of a substance divided by the urine volume per unit of time

Answer 6

a. Volume of plasma from which a substance is removed per unit of time

Question 7

Renin release by the kidney is stimulated by
a. A decrease in extracellular fluid volume or pressure
b. Increased plasma sodium concentration
c. Increased dietary sodium
d. Renal tubular reabsorption

Answer 7

a. A decrease in extracellular fluid volume or pressure

Question 8

The set of results that most accurately reflects severe renal disease is
a. Serum creatinine, 3.7 mg/dL; creatinine clearance, 44 mL/min; BUN,
88 mg/dL
b. Serum creatinine, 1.0 mg/dL; creatinine clearance, 110 mL/min; BUN,
17 mg/dL
c. Serum creatinine, 2.0 mg/dL; creatinine clearance, 120 mL/min; BUN,
14 mg/dL
d. Serum creatinine, 1.0 mg/dL; creatinine clearance, 95 mL/min; BUN,
43 mg/dL

Answer 8

a. Serum creatinine, 3.7 mg/dL; creatinine clearance, 44 mL/min; BUN,
88 mg/dL

Question 9

Creatinine clearance results are corrected using a patient’s body surface area to
account for differences in
a. Muscle mass
b. Age
c. Dietary intake
d. Sex

Answer 9

a. Muscle mass

Question 10

A patient is suffering from an acute bleed. What is the most accurate way to
describe the subsequent acute kidney injury?
a. Prerenal acute kidney injury.
b. Renal acute kidney injury.
c. Postrenal acute kidney injury.
d. None of the above apply.

Answer 10

a. Prerenal acute kidney injury.