Calculate urine albumin-to-creatinine ratio (ACR) with KDIGO staging. Classifies microalbuminuria, macroalbuminuria, and CKD prognosis by GFR and albuminuria.
The Albumin-to-Creatinine Ratio (ACR) Calculator converts spot urine albumin and creatinine measurements into the standardized ACR used for kidney disease screening and staging. It classifies results per KDIGO guidelines (A1, A2, A3), identifies microalbuminuria and macroalbuminuria, and combines ACR with eGFR to determine CKD prognosis risk category.
The urine ACR is the preferred method for detecting early kidney damage because it corrects for urine concentration by normalizing albumin to creatinine. A spot urine ACR correlates well with 24-hour albumin excretion, making it far more practical for screening. Abnormal ACR is one of the earliest detectable signs of diabetic nephropathy and hypertensive kidney disease, often preceding eGFR decline by years.
This calculator handles multiple input units (mg/L, mg/dL for albumin; g/L, mg/dL, mmol/L for creatinine), applies sex-specific normal thresholds, and provides the full KDIGO prognosis heat map combining GFR and albuminuria categories. Use it for routine diabetes and hypertension screening, CKD staging, and monitoring treatment response.
Early detection of albuminuria enables interventions (ACE inhibitors, SGLT2 inhibitors, BP control) that slow kidney disease progression. The ACR is the simplest and most cost-effective test for kidney screening in diabetes and hypertension care. Keep these notes focused on your operational context. Tie the context to the calculator’s intended domain. Use this clarification to avoid ambiguous interpretation.
ACR (mg/g) = (Urine Albumin [mg/L]) / (Urine Creatinine [g/L]) A1: <30 mg/g | A2: 30-300 mg/g | A3: >300 mg/g Sex-specific normals: Male <17 mg/g, Female <25 mg/g
Result: ACR = 80 mg/g, A2 (Moderately increased / Microalbuminuria)
An ACR of 80 mg/g falls in the A2 category (30-300), indicating microalbuminuria. Combined with the eGFR, this determines the CKD risk level per KDIGO guidelines.
Diabetic nephropathy progresses through predictable stages: normoalbuminuria → microalbuminuria → macroalbuminuria → declining GFR → ESRD. The ACR is the most sensitive tool for detecting the transition from normal to microalbuminuria. Intervention at this stage (intensive glucose control, RAS blockade, SGLT2 inhibitors) can halt or reverse progression.
The KDIGO 2012 guidelines classify CKD risk using a 2-dimensional matrix: GFR categories (G1-G5) on one axis and albuminuria categories (A1-A3) on the other. The resulting "heat map" ranges from green (low risk) to red (very high risk) and determines monitoring frequency, treatment thresholds, and referral indications.
Beyond kidney disease, an elevated ACR independently predicts cardiovascular events, stroke, and all-cause mortality. Even microalbuminuria (A2) is associated with 2-3× increased cardiovascular risk, regardless of eGFR. This makes ACR a valuable addition to standard cardiovascular risk assessment frameworks.
Microalbuminuria is defined as ACR 30-300 mg/g (KDIGO A2). It indicates early kidney damage and is a marker of generalized endothelial dysfunction and cardiovascular risk.
Spot urine ACR correlates well with 24-hour albumin excretion and is far more practical. A first morning void is preferred to minimize postural and exercise effects.
ADA and KDIGO recommend annual ACR screening in all type 2 diabetes patients from diagnosis and in type 1 patients starting 5 years after diagnosis. Use this as a practical reminder before finalizing the result.
Yes — exercise, UTI, fever, heart failure, menstruation, and very dilute urine can transiently increase albumin. Confirm abnormal results with repeat testing on 2 of 3 samples over 3 months.
Albumin is a specific protein; proteinuria includes all proteins. ACR specifically measures albumin, which is the most sensitive marker for glomerular damage. Total protein/creatinine ratio (PCR) captures other proteins too.
Men typically excrete more creatinine due to higher muscle mass, which dilutes the ratio. Sex-specific thresholds improve sensitivity — <17 mg/g for males and <25 mg/g for females are considered truly normal.