Urine microalbumin is a very sensitive and objective indicator of kidney function, and clinically, urine microalbumin is almost undetectable or has very low values. If urine microalbumin is found to be mildly elevated, patients are advised to review the test again. If the results are still elevated, specific diseases need to be excluded. Elevated urine microalbumin is caused by chronic nephritis, hypertension, hypertension during pregnancy, diabetes, and internal diseases that can cause elevated urine microalbumin. Because the kidneys are damaged by these diseases resulting in decreased filtration rate and damaged basement membrane, urinary microalbumin can cross the normal or damaged kidney filtration membrane and thus elevated urinary microalbumin levels are found in the urine. Elevated urine microalbumin is only a sensitive indicator of the kidney and does not necessarily mean that the disease is irreversible. If abnormalities are detected, timely treatment can also bring the disease under control or reverse it.