Albumin is a protein that is present in large amounts in the blood. When kidneys are functioning properly, only a tiny amount of albumin leaks through into the urine, less than 30 mg/day. In kidney failure (the last stage of a slow process of decline in kidney function), large amounts of protein are spilled into the urine.

Reference Values

The ratio of albumin (mcg/L) to creatinine (mg/L) of less than 30 is normal; a ratio of 30-300 highlights microalbuminuria and Ranges above 300 are measured as macroalbuminuria. On a standard urine dipstick, 10-20 mg/dL is the minimal detection limit of protein.

Interpretations

Moderately increased UACR levels in urine indicate that a person is in one of the very early phases of developing kidney disease. Recently, studies have shown that an abnormal UACR result indicates an increased risk of developing heart and blood vessel (cardiovascular) complications, especially in people with diabetes. Low levels are an indication that kidney function is normal. Moderate to high, persistently elevated levels of albumin in urine over three to six months is a requirement for establishing a diagnosis.