Creatinine Clearance (from Serum)

What Is Creatinine Clearance?

Creatinine clearance is a measure of kidney function that estimates how well your kidneys filter waste products like creatinine from your blood. Unlike a single creatinine blood test, this test considers both your creatinine levels and your urine output over time to provide a more accurate picture of kidney health. It helps doctors determine how well your kidneys are working to remove waste and maintain fluid balance in your body.

How Is This Test Performed?

For this test, a blood sample is taken from a vein in your arm to measure creatinine levels in your serum. Additionally, a urine sample is collected over a 24-hour period to measure how much creatinine is excreted in your urine. The results are then used to calculate your creatinine clearance rate.

Why Might You Need This Test?

Your doctor may order a creatinine clearance test if they suspect kidney disease, monitor kidney function in people with chronic kidney disease, evaluate kidney function before certain surgeries or medical procedures, or assess how medications are being processed by your kidneys.

What Do the Results Mean?

Results are typically reported as a clearance rate in milliliters per minute (mL/min). Lower clearance rates may indicate impaired kidney function, while higher rates suggest normal or better-than-average kidney function. However, specific reference ranges can vary by lab and individual health status.