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

What Is Creatinine Clearance Used For?

Creatinine clearance is primarily used to evaluate kidney function and diagnose or monitor kidney disease. It’s a key tool for doctors to determine if your kidneys are working properly and to check for early signs of kidney damage.

How Is This Test Done?

To calculate creatinine clearance, you’ll typically provide a blood sample (serum/plasma) and a 24-hour urine sample. The blood test measures creatinine levels, while the urine sample measures creatinine excretion over 24 hours. Your doctor may also use a formula that estimates glomerular filtration rate (GFR) based on your age, gender, and blood creatinine level.

Why Might Your Doctor Order This Test?

Your doctor may order creatinine clearance if they suspect kidney problems, such as chronic kidney disease, kidney stones, or other conditions affecting kidney function. It’s also used before surgeries, during pregnancy, or if you have conditions like diabetes or high blood pressure that can impact kidney health.

What Does a Low or High Clearance Mean?

A lower than expected creatinine clearance suggests impaired kidney function, meaning your kidneys may not be filtering waste as well as they should. A higher clearance might indicate overhydration or other factors affecting kidney output, but this is less common and requires further evaluation.