Kidney

Urine Microalbumin (ACR) Test Explained

The ACR test detects tiny amounts of protein leaking into urine — often the earliest sign of kidney damage in diabetes and high blood pressure, years before symptoms.

Normal ACR
<3 mg/mmol
Microalbuminuria
3-30 mg/mmol
Macroalbuminuria
>30 mg/mmol
Tested in
All diabetics annually

Why This Test Matters

Healthy kidneys prevent protein from leaking into urine. Even small amounts (microalbuminuria) indicate early kidney damage, commonly from diabetes or high blood pressure, well before creatinine or eGFR become abnormal.

ACR Categories

CategoryACR (mg/mmol)Significance
Normal<3No significant kidney damage detected
Microalbuminuria (A2)3-30Early kidney damage — important to treat aggressively
Macroalbuminuria (A3)30+Significant kidney damage — higher cardiovascular and kidney failure risk
Treatment Reduces ProgressionACE inhibitors or ARBs specifically reduce protein leakage and slow kidney damage progression in diabetics with microalbuminuria — even if blood pressure is already normal, these medications are often still recommended for their protective effect.
Can microalbuminuria be reversed?
With good blood sugar and blood pressure control, and ACE inhibitor/ARB treatment, microalbuminuria can sometimes improve or stabilise, though established macroalbuminuria is harder to reverse.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.