Urine Albumin/Creatinine Ratio
Calculate ACR from a spot urine sample to detect early kidney damage, stratify risk, and tailor renoprotective therapy.
Random spot urine albumin (immunoassay). Use mg/L or mg/dL.
Creatinine from the same urine sample. Most labs report mg/dL.
How to Use This Calculator
Use an early-morning spot urine sample
Follow KDIGO guidelines by using a first-morning void to minimise variability in albumin excretion.
Enter albumin and creatinine results
Choose the units reported by your laboratory. The calculator converts automatically to standard mg/g and mg/mmol outputs.
Interpret in the clinical context
Confirm elevated ACR with repeated tests over 3–6 months and assess CKD staging alongside eGFR, blood pressure, and comorbid conditions.
Formula
ACR (mg/g) = (Urine albumin (mg/L)) ÷ (Urine creatinine (g/L))
ACR (mg/mmol) = ACR (mg/g) ÷ 8.84
Where urine creatinine (g/L) = Creatinine (mg/dL) × 0.01.
Full Description
The albumin-to-creatinine ratio quantifies albuminuria and complements estimated GFR to stage chronic kidney disease per KDIGO guidelines. Persistent ACR elevation predicts cardiovascular morbidity and CKD progression. Optimise blood pressure control (ACE inhibitors/ARBs), glycaemic management, and lifestyle interventions. Repeat measurements after 3 months to confirm chronicity and evaluate for transient causes such as urinary tract infection, heart failure, or intense exercise.
Frequently Asked Questions
Should I use 24-hour urine collections?
Spot urine ACR correlates strongly with 24-hour collections and is recommended for routine screening. Reserve timed collections for atypical cases.
How do I handle biologic variability?
Albumin excretion varies day-to-day. Confirm elevated results with at least two abnormal readings out of three over 3–6 months.
Do I need to adjust for sex or race?
Standard ACR thresholds are applied universally. Interpretation should still consider muscle mass, hydration status, and comorbidities.
What if creatinine is very low?
Very dilute urine (low creatinine) can overestimate ACR. Repeat testing with a first-morning sample or timed collection if results are unexpected.