Question: Assume you want to evaluate kidney function in a 55-year¬-old, obese man with type II diabetes,and you ask him to collect his urine over a 24 hour period. He returns to you 4,320 mL of urine, which was collected over the preceding 24 hours. The clinical laboratory returns the following results from analysis of his urine and plasma samples:
Plasma creatinine = 3.0 mg/100 mL
Urine creatinine = 40 mg/100 mL
Plasma potassium = 5.0 mmol/L
Urine potassium = 20 mmol/L
What is his approximate GFR, assuming that he collected all of his urine in the 24 hour
period?
A.10 mL/min
B.20 mL/min
C.30 mL/min
D.40 mL/min
E.80 mL/min