Only traces of protein should be found in the urine of normal individuals. The presence of protein in the urine, particularly albumin, is a sign of kidney disease often caused by diabetes or hypertension. The earlier the kidney disease is diagnosed, the more effective the treatment will be. Microalbuminuria screening is a test that can detect very small amounts of protein in the urine before the routine urine protein result comes out positive. Microalbuminuria is most often measured on a single (spot) urine sample and results are expressed as milligrams of microalbumin per millimole of creatinine (mg/mmoll).
Clinical microalbuminuria is defined as a microalbumin result between 2 and 20 mg/mmol. A microalbumin level over 20 mg/mmol is consistent with frank albuminuria or frank proteinuria. A normal result is defined as any microalbumin level below 2 mg/mmol or the indication that microalbumin was undetectable (<5 mg/L).