In creatinine clearance calculation using the standard urine collection method, the result is expressed in which units?

In creatinine clearance calculation using the standard urine collection method, the result is expressed in which units?

• A. mL/min
• B. mL/day
• C. L/min
• D. L/day

Answer: (A)

Creatinine clearance is a rate: it tells you how much plasma is cleared of creatinine per unit time. In the standard urine collection method you measure the amount of creatinine excreted in urine over a 24-hour period and relate it to the plasma creatinine. The formula Ccr = (Ucr × V) / Pcr uses V as urine flow. To express the result as a rate, you convert the total 24-hour urine volume to a per-minute rate by dividing by 1440 minutes. That gives you Ccr in milliliters per minute, which is the conventional way to report clearance and aligns with GFR units. Using milliliters per day would represent a total daily amount, not a rate, and liters per minute or per day are not standard for this measurement.

Creatinine clearance is a rate: it tells you how much plasma is cleared of creatinine per unit time. In the standard urine collection method you measure the amount of creatinine excreted in urine over a 24-hour period and relate it to the plasma creatinine. The formula Ccr = (Ucr × V) / Pcr uses V as urine flow. To express the result as a rate, you convert the total 24-hour urine volume to a per-minute rate by dividing by 1440 minutes. That gives you Ccr in milliliters per minute, which is the conventional way to report clearance and aligns with GFR units. Using milliliters per day would represent a total daily amount, not a rate, and liters per minute or per day are not standard for this measurement.