Creatinine Clearance (Calculated from Serum Creatinine and Estimated Glomerular Filtration Rate)

What Is Creatinine Clearance Used For?

Creatinine clearance helps doctors evaluate kidney health by estimating how much blood your kidneys filter each minute. It’s often used alongside serum creatinine tests to diagnose or monitor kidney disease, especially in cases where kidney function may be impaired or unclear.

How Is This Test Done?

This is a calculated test, not drawn directly from a blood sample. Instead, your healthcare provider uses your serum creatinine level (from a blood test) and an estimated glomerular filtration rate (eGFR) to compute clearance. Sometimes, a 24-hour urine sample may be used to measure urine creatinine and urine volume for a more precise calculation.

Why Might You Need This Test?

You may need creatinine clearance if you have symptoms of kidney problems (like fatigue, swelling, or frequent urination), are at risk for kidney disease (e.g., due to diabetes, high blood pressure, or a family history), or are undergoing treatment that could affect kidney function (e.g., certain medications). It’s also used before surgeries or procedures that may impact kidney function.

What Does a Low or High Clearance Mean?

A lower-than-expected clearance suggests impaired kidney function, meaning your kidneys may not be filtering blood as well as they should. A higher-than-expected clearance is less common but could indicate overestimation of kidney function or conditions like polycystic kidney disease.