This kit is used for quantitative determination of microalbumin (MAU) in human urine in vitro. Urinary microalbumin (MAU) is a non glycosylated albumin with a molecular weight of 6.9kd. It is one of the smallest protein molecules that can pass through glomerular filtration membrane, accounting for 40% of the total filtration protein. Almost all of the glomerular filtration proteins are actively absorbed by the proximal convoluted tubules, so there is only Microalbumin in the urine. The excretion of microalbumin in urine is affected by many factors, such as body position, exercise, blood pressure, protein intake and so on. Under normal circumstances, most of the proteins can not pass through the filtration membrane. However, in pathological conditions, such as various kinds of inflammation, metabolic abnormalities and immune damage, the glomerular hemodynamics is abnormal, and the glomerular filtration membrane damage is an important reason for the increase of urinary microalbumin output. The appearance of urinary microalbumin is a sign of early renal injury.