Microalbumin refers to the presence of microalbumin in human urine. Albumin is a normal protein in the blood, but only a small amount of albumin appears in urine under physiological conditions. Microalbuminuria reflects abnormal leakage of protein in human kidneys. In clinical practice, microalbumin are usually used to monitor the occurrence of nephropathy. The detection of microalbumin is the most sensitive and reliable diagnostic indicator for early detection of kidney disease. Microalbumin is also a sign of changes in the entire vascular system and can be considered a "window" for arterial disease because it is an early indication of changes in the kidneys and cardiovascular system.