Proteinuria (also called albuminuria or urine albumin) is a condition in which urine contains an abnormal amount of protein. Albumin is the main protein in the blood. Proteins are the building blocks for all body parts, including muscles, bones, hair, and nails. Proteins in the blood also perform a number of important functions. They protect the body from infection, help blood clot, and keep the right amount of fluid circulating throughout the body.
Proteinuria is a sign of chronic kidney disease (CKD). If CKD progresses, it can lead to end-stage renal disease (ESRD), when the kidneys fail completely. A person with ESRD must receive a kidney transplant or regular blood-cleansing treatments called dialysis.