Creatinine Clearance (from Serum)

What Is Creatinine Clearance?

Creatinine clearance is a measure of how well your kidneys are removing creatinine, a waste product from muscle metabolism. Unlike simple creatinine blood tests, this method accounts for your body size and urine output to give a more accurate picture of kidney function. It’s often used to diagnose or monitor kidney disease, especially in cases where kidney function may be impaired but creatinine levels alone are unclear.

How Is This Test Performed?

For this test, a blood sample is taken from a vein (usually in your arm) to measure creatinine levels in your serum. You’ll also provide a 24-hour urine sample to measure how much creatinine is excreted. The results are then used to calculate your creatinine clearance rate.

Why Might You Need This Test?

Your doctor may order creatinine clearance if they suspect kidney disease, monitor kidney function over time, or evaluate kidney function in people with conditions like diabetes, high blood pressure, or chronic illnesses. It’s also used before surgeries or procedures that may affect kidney function.

What Are the Results?

Results are typically expressed in milliliters per minute (mL/min). While exact reference ranges can vary by lab, lower than expected values may indicate kidney problems, while higher values could suggest dehydration or other conditions. Your doctor will interpret the results in the context of your overall health.