Clinical Significance:
Normally, the kidneys work to filter waste products, water, and other chemicals from the blood and send them to the bladder where they are excreted in the form of urine. In the earliest stage of diabetic nephropathy, abnormally large amounts of blood flow through the nephrons, the tiny filters within the kidneys. This condition is known as hyper filtration. Due to hyper filtration there is leakage of proteins in the urine from the kidney cells. One such protein is albumin. Proteinuria is the presence of protein in the urine. Most proteins are too large to pass through the glomeruli into the urine. But when the glomeruli are damaged, proteins of various sizes pass through them and are excreted in the urine. This will create a condition called microalbuminuria.
Microalbuminuria is defined as the excretion of 30-300 mg of albumin per day in the urine. It is not a different form of albumin, just a very small amount of albumin. Because the albumin molecule is relatively small, it is often among the first protein to enter the urine after the kidney is damaged. Therefore, even minor kidney dysfunction is detectable with proper diagnosis of small quantities of albumin.
