Urinary Creatinine-to-Creatinine Clearance Ratio (24-hour urine)

What Does This Test Measure?

The test evaluates kidney function by comparing the amount of creatinine in your urine to the amount in your blood over a 24-hour period. Creatinine is a waste product from muscle metabolism that kidneys filter out. This ratio helps determine how efficiently your kidneys are removing waste and maintaining fluid balance.

Why Is This Test Done?

Your doctor may order this test if you have symptoms like frequent urination, swelling, high blood pressure, or signs of kidney disease. It’s also used to monitor kidney function in people with diabetes, heart disease, or other conditions that affect kidney health.

How Is This Test Performed?

You’ll collect all your urine for 24 hours in a special container. Your doctor will provide instructions on timing and storage. Blood may also be drawn to measure baseline creatinine levels. The urine and blood samples are then sent to a lab for analysis.

What Are Possible Results?

Results are typically expressed as a ratio (e.g., mL/min) or as a clearance value. Lower than expected ratios may indicate poor kidney function, while higher values could suggest overhydration or other conditions. Your doctor will interpret results in relation to your health and symptoms.