MCL Web Resources
Pathology Services
CREATININE CLEARANCE (24-HOUR):
Special Collection:
- If the shorter tests is to be performed, hydrate the patient by administration of a
minimum of 600 ml of water.
- 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).
Calculation: ml of plasma cleared per minute per standard surface area equals:
where:
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.
P = 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 standard nomogram.