- Collect 24 hour urine for creatinine. Note exact time of collection (i.e., 23,
24, or 25 hours; 23 hrs. 30 min., etc.)
- Collect blood for serum creatinine at some time during the urine collection
(or within 36 hr of urine collection).
- Document height and weight.
ml of plasma cleared per minute per standard surface area equals:
U =concentration of
creatinine in urine in mg/dl Before
calculation, multiply total creatinine excreted
(reported as g/L) by 100 to obtain mg/dl.
concentration of creatinine in plasma in mg/dl.
V = volume of
urine in ml divided by the time of collection in minutes.
A = body
surface area in square meters. Calculate body surface area of patient from