24-Hour Urinary Albumin-to-Creatinine Ratio (Albumin-to-Creatinine Ratio, 24-Hour Urinary Albumin Excretion Rate)

Why This Test Matters for Kidney Health

Albumin is normally kept in your bloodstream by healthy kidneys. When kidney function weakens, small amounts of albumin can leak into urine. This test quantifies that leakage over a full day, providing a more accurate picture than a single urine sample. It’s especially useful for people with diabetes or high blood pressure, as these conditions can damage kidneys over time.

How the Test Works

You’ll collect all your urine for 24 hours in a special container. The lab then measures the amount of albumin in your urine relative to creatinine (a waste product from muscles). This ratio helps determine if your kidneys are allowing too much protein into urine, which can signal early kidney issues.

What to Expect Before the Test

No special preparation is needed beyond collecting all urine for 24 hours. Drink enough fluids to produce urine throughout the day, but avoid excessive alcohol or caffeine, which might affect results. Start and end the collection at the same time each day (e.g., midnight to midnight).

What to Expect During the Test

You’ll provide a single urine sample after completing the 24-hour collection. The lab processes this sample to calculate the albumin-to-creatinine ratio or albumin excretion rate. Results are typically ready within a few days.