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Kaplan Qbank USMLE



Author6 Posts
  #1

A 45-year-old woman is hospitalized after an automobile accident.
The physician collects 1.44 L of urine from the patient in a
24-hour period. The clinical lab returns the following results:
Plasma creatinine concentration 2.0 mg/mL
Plasma urea concentration 15 mmol/mL
Urine creatinine concentration 100 mg/mL
Urine urea concentration 160 mmol/mL
What is the approximate glomerular filtration rate (GFR; in mL/min)
of this patient?
A. 10
B. 25
C. 50
D. 75
E. 100

  #2

E :?:

  #3

It should be D...U times V over P

1.44 times 100 divided by 2 is ~ 75

  #4

crap...forgot it was in a day.

1.44L/day X 100 mg/mL / 2.0 mg/mL = 72L/day = 72000mL/day

72000mL/1440min = 50mL/min

:oops:

  #5

ANother trick is this:

serum creatinine should be 1. For every doubling in creatinine, the GFR gets cut in half. If you couldnt figure it out, you could use this formula.

  #6

thanks smiling face







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