24-Hour Urinary Creatinine Clearance Rate

What This Test Measures

Creatinine is a waste product naturally produced in your body from muscle metabolism. Healthy kidneys filter creatinine from your blood and excrete it in urine. This test evaluates how well your kidneys clear creatinine over 24 hours, which helps assess kidney function and detect early signs of kidney disease.

Why It’s Done

Your healthcare provider may order this test if you have symptoms of kidney problems (such as fatigue, swelling, or frequent urination), if you have a history of kidney disease, or if you’re being monitored for conditions like diabetes or high blood pressure that can affect kidney function. It’s also used to evaluate kidney function in people with chronic conditions or after certain treatments.

How It’s Done

You’ll collect all your urine for a full 24-hour period in a special container. The test involves measuring the amount of creatinine in your urine and comparing it to a blood sample taken at the start of the collection period. This helps calculate your creatinine clearance rate.

Sample Preparation

No special preparation is needed, but you’ll need to empty your bladder completely before starting the collection and discard the first urine sample. After that, collect all urine for the full 24 hours, including any overnight urine. Store the urine in a cool, dark place until you return it to the lab.