24-Hour Urinary Creatinine Clearance

Why This Test Matters

Your kidneys play a critical role in filtering waste and excess substances from your blood. This test helps doctors check if your kidneys are working properly by measuring how much creatinine (a waste product) your body removes through urine over a full day. It’s useful for diagnosing or monitoring kidney disease, especially when blood tests alone may not provide enough information.

How the Test Works

You’ll collect all your urine for 24 hours and provide a single blood sample. The lab will compare the amount of creatinine in your urine to your blood creatinine levels to calculate how efficiently your kidneys filter waste.

Sample Collection Process

Start by discarding your first morning urine. Collect every urine sample in a container for the next 24 hours, keeping it refrigerated if needed. On the 24th hour, collect your final urine sample and provide a blood sample at your doctor’s office or lab. Avoid certain medications and foods that may affect results.

What to Expect After the Test

You’ll receive your results from your healthcare provider, who will interpret them in relation to your overall health. Low clearance may indicate kidney problems, while normal results suggest healthy filtration.