Creatinine Clearance (from 24-hour urine collection)

Why This Test Is Done

Your doctor may order this test if they suspect kidney disease, need to monitor kidney function before or after treatment, or want to evaluate how well medications are being processed by your kidneys. It’s also used to diagnose conditions like chronic kidney disease or to check for kidney damage from certain illnesses or medications.

What to Expect Before the Test

You’ll need to collect all urine for a full 24-hour period (typically from one morning to the next morning). Drink plenty of fluids but avoid excessive caffeine or alcohol. Follow your doctor’s instructions carefully to ensure accurate results.

How the Test Works

Your urine sample is tested for creatinine, a waste product from muscle metabolism. The test also measures the volume of urine collected. The clearance rate compares how much creatinine is filtered by your kidneys relative to your blood flow, providing a snapshot of kidney function.

What the Results Mean

Results are usually reported as a clearance rate (e.g., in milliliters per minute or liters per day). Lower than expected values may indicate kidney problems, while higher values could suggest overhydration or other conditions. Your doctor will interpret results in the context of your overall health.