Creatinine Clearance (from 24-hour urine collection)

What Does This Test Measure?

Creatinine clearance evaluates how efficiently your kidneys remove creatinine—a waste product from muscle metabolism—from your blood. It’s calculated by comparing the amount of creatinine in your urine over 24 hours with your urine volume and blood creatinine levels. Unlike a single blood test, this method provides a more accurate picture of kidney function over time.

Why Is This Test Important?

This test is particularly useful for diagnosing or monitoring chronic kidney disease (CKD), kidney damage from conditions like diabetes or high blood pressure, or kidney function before surgeries or procedures that may affect blood flow to the kidneys.

When Might You Need This Test?

Your doctor may recommend this test if you have symptoms like fatigue, swelling, frequent urination, or if you have a history of kidney-related conditions. It’s also used in certain medical settings to assess kidney health before treatments or procedures.

How Is the Test Performed?

You’ll collect all your urine for a full 24-hour period in a special container. At the start and end of the day, you’ll provide a blood sample to measure your baseline creatinine level. The test involves analyzing the urine and blood samples together to calculate clearance.