The Albumin-Creatinine Ratio (ACR) test on a spot urine sample is a simple and highly effective screening tool used to detect early signs of kidney damage, particularly in individuals with diabetes or high blood pressure.

Rather than requiring a cumbersome 24-hour urine collection, this test measures the amount of albumin (a vital protein) relative to creatinine (a waste product) in a single, random urine sample.

Under normal conditions, healthy kidneys filter out waste while keeping large proteins like albumin in the blood. A high ACR ratio indicates that albumin is leaking into the urine, serving as an early warning sign of chronic kidney disease (CKD) so treatment can start immediately.