UACR (Urine Albumin-to-Creatinine Ratio)

The urine albumin-to-creatinine ratio (UACR) is a simple urine test that measures whether the kidneys are leaking small amounts of a protein called albumin into the urine — often one of the earliest detectable signs of kidney damage.

Why It Detects Problems Early

Healthy kidneys normally keep albumin in the blood rather than letting it pass into urine. When the kidneys' filtering units are damaged, even mildly, small amounts of albumin can start leaking through — often well before blood-based kidney tests like creatinine or eGFR show any change. This makes UACR a valuable early-warning test, particularly for people at higher risk.

Who Should Be Tested

Regular UACR testing is especially recommended for people with diabetes or high blood pressure, both of which are leading causes of kidney damage that can develop silently. Diabetes-care guidelines generally recommend UACR testing at least once a year for people with diabetes, with more frequent monitoring once kidney damage is identified. Diabetes-care guidelines generally recommend UACR testing at least once a year for people with diabetes, with more frequent monitoring once kidney damage is identified. Diabetes-care guidelines generally recommend UACR testing at least once a year for people with diabetes, with more frequent monitoring once kidney damage is identified. Our diabetes and kidney function tests guides cover the broader picture of kidney monitoring for these conditions.

Understanding Results

A normal UACR is generally below 30 mg/g. Higher levels indicate increasing amounts of albumin leakage and are generally categorized as moderately increased (roughly 30 to 300 mg/g) or severely increased (above 300 mg/g), which helps doctors assess kidney damage severity and monitor changes over time. Since factors like recent vigorous exercise, urinary tract infection, or fever can temporarily affect results, an elevated reading is usually confirmed with repeat testing.