albumintocreatinine

The albumin-to-creatinine ratio (ACR) is a urine test used to estimate how much albumin is being excreted in the urine relative to creatinine. It is commonly measured from a spot urine sample, which can be random or first-morning. The result is expressed as milligrams of albumin per gram of creatinine (mg/g) or milligrams per millimole (mg/mmol), with creatinine accounting for urine concentration.

Normal values are typically considered less than 30 mg/g. Values from 30 to 300 mg/g indicate microalbuminuria (moderately increased albumin), while values above 300 mg/g indicate macroalbuminuria (severely increased albumin). ACR is used to screen for kidney disease and to monitor progression, especially in people with diabetes mellitus or hypertension.

ACR is preferred to a 24-hour urine collection because it is convenient and has good reproducibility. However, results can be affected by factors such as recent exercise, fever, dehydration, urinary tract infection, or high protein intake. When an elevated ACR is detected, repeat testing on a separate day is usually advised to confirm persistence. Reference ranges can vary by age, sex, and population, so laboratory-specific norms may apply.

Clinical use includes early detection of diabetic nephropathy, risk stratification in chronic kidney disease, and monitoring response to therapy. Guidelines from major health organizations incorporate ACR as a standard measure in kidney health assessment, helping identify individuals at risk for kidney-related complications.