What is proteinuria?
Proteinuria, also known as albuminuria or urine albumin, is a condition indicated by an abnormal amount of protein in the urine. Proteinuria is a sign of chronic kidney disease (CKD).
Proteins are the building blocks for all body parts and the main protein in blood is albumin. As blood passes through healthy kidneys, the kidneys filter out waste products and leave vital proteins such as albumin and other substances the body needs. Most proteins are too big to pass through the filters in the kidneys (glomeruli) into the urine. However, if the kidney filters are damaged, proteins from the blood can leak into the urine.
In its early stages, proteinuria has no signs or symptoms. In later stages, large amounts of protein in the urine have recognizable symptoms:
- Foamy urine
- Swelling in the hands, feet, abdomen or face
- Reduced glomerular filtration rate. This indicates inefficient filtering of wastes from the blood.
- People with diabetes, hypertension or certain family backgrounds are at risk for proteinuria.
- Albumin in the urine is one of the first signs of deteriorating kidney function for people who have type 1 or type 2 diabetes. As kidney function declines, the amount of albumin in the urine increases.
- Hypertension or high blood pressure is a risk factor for developing proteinuria. For a person with high blood pressure, proteinuria is a symptom of declining kidney function. Uncontrolled hypertension ultimately can lead to full kidney failure.