Serum Creatinine Clearance (Rate)

What Is Creatinine Clearance?

Creatinine clearance is a measure of how effectively your kidneys filter waste products like creatinine from your blood. Unlike a single creatinine level, this test evaluates your kidneys' long-term ability to clear waste over time, often using a 24-hour urine collection or a simplified formula based on blood and urine samples.

Why Is This Test Done?

Your doctor may order creatinine clearance to check for kidney problems, monitor kidney disease progression, or evaluate kidney function before certain treatments. It’s also useful in cases where kidney function might be affected by medications, dehydration, or other health conditions.

How Is It Done?

The test typically involves two parts: a blood sample (serum/plasma) and a urine sample. For a 24-hour urine test, you collect all urine over a full day. For a simplified method, a single blood and urine sample may be taken, with a formula applied to estimate clearance. The blood sample measures creatinine levels, while the urine sample measures creatinine excretion.

What Do Results Mean?

Results are compared to standard values based on age, sex, and body size. Lower than expected clearance may indicate kidney damage or reduced function, while higher values might suggest overhydration or other conditions. Your doctor will interpret results in the context of your overall health.