24-Hour Creatinine Clearance (from urine and serum)

Why Is This Test Done?

Your doctor may order this test to check if your kidneys are working properly, especially if you have symptoms like fatigue, swelling, or changes in urine output. It helps diagnose kidney disease, monitor chronic conditions like diabetes or high blood pressure, or evaluate kidney function before certain treatments.

What to Expect Before the Test

You’ll collect a 24-hour urine sample starting from one point in the morning until the same time the next morning. Store the urine in a refrigerator and bring the entire sample to your lab visit. On the same day, a blood sample will be taken to measure your creatinine level.

What Happens During the Test?

The urine sample is tested for creatinine concentration, while the blood sample measures your baseline creatinine level. These values are then used to calculate how efficiently your kidneys filter waste from your blood.

What Are the Results Measured Against?

Results are typically expressed as milliliters per minute (mL/min) or milliliters per second (mL/s). This test helps determine if your kidney function is within a healthy range or if further medical evaluation is needed.