24-Hour Urinary Creatinine Clearance

What Does This Test Measure?

Creatinine is a waste product from muscle metabolism that your kidneys normally filter out of your blood. This test measures how much creatinine appears in your urine over 24 hours, along with the volume of urine produced. The result helps determine how effectively your kidneys are removing waste and maintaining fluid balance.

Why Is This Test Done?

Your doctor may order this test if you have symptoms of kidney disease (such as fatigue, swelling, or frequent urination), if you have a history of kidney problems, or if you’re taking medications that can affect kidney function. It’s also used to monitor kidney function in people with diabetes, high blood pressure, or other chronic conditions that can impact the kidneys.

How Is This Test Performed?

You’ll need to collect all urine for a full 24-hour period, starting after you wake up the first morning. Typically, you’ll empty your bladder at the start and then collect every bit of urine for the next 24 hours. The urine is then sent to a lab for testing. Blood may also be drawn to measure creatinine levels in your bloodstream for comparison.

What Are the Results?

Results are typically expressed as the volume of urine (in liters) filtered by your kidneys per minute (measured in milliliters per minute, or mL/min). A lower clearance rate may indicate reduced kidney function, while a higher rate may suggest overhydration or other conditions. Your doctor will interpret the results in relation to your overall health and symptoms.