The albumin-to-creatinine ratio (ACR) is a quantitative assessment of albuminuria, a condition characterized by the presence of abnormally high levels of albumin in the urine. It is calculated by dividing the albumin concentration in a urine sample (measured in milligrams) by the creatinine concentration in the same sample (measured in grams). For example, if a urine sample contains 30 mg of albumin and 1 gram of creatinine, the ACR would be 30 mg/g. This ratio provides an estimate of the amount of albumin excreted in the urine relative to the concentration of creatinine.
The significance of this ratio lies in its ability to detect early signs of kidney disease and to monitor its progression. Elevated levels often indicate kidney damage, which can stem from conditions like diabetes, hypertension, or glomerulonephritis. Early detection allows for timely intervention, potentially slowing the disease’s progression and reducing the risk of complications. The introduction of ACR testing has significantly improved the diagnosis and management of kidney disease compared to older methods, offering a more accurate and convenient assessment than traditional 24-hour urine collections.