Proteinuria (Protein in the Urine)
Proteinuria is an abnormal condition in which urine contains high amounts of protein. Proteins are important building blocks of all parts of the body, including muscles and bones. Blood also contain these substances that help to protect the body from infections; help to form clots; and help keep the right amounts of fluid throughout the body.
Normally, waste products are filtered out from the blood by healthy kidneys. Proteins and other needed materials are left in the blood. Most proteins are too large to pass through the kidney’s filters. However, these proteins from the blood can leak into the urine if the kidneys are damaged. The protein that is more likely to appear in urine is albumin. Albuminuria is a term used often when urine tests detect albumin specifically.
Glomerulonephritis, or simply nephritis, is a term used to indicate inflammation in the glomeruli, the actual tiny filtering units of the kidneys. There are different diseases that can cause this inflammation, which can lead to proteinuria. Diabetes, hypertension, and other forms of kidney diseases can cause proteins to seep out by damaging the glomeruli.
You may be at risk for proteinuria if you
- have diabetes
- have high blood pressure or hypertension
- are overweight
- have a family history of kidney disease
If you think that you are at risk of developing the condition, you should ask your doctor about having your urine tested. Several health organizations recommend that people be regularly checked for proteinuria so that kidney problems can be detected and treated or prevented before it progresses.
Signs and symptoms of the condition may include foamy urine and swelling in the hands, feet, abdomen, or the face. These signs result from too much loss of proteins. Some people may have proteinuria without noticing any signs or symptoms. The only way to find out how much protein you have in your urine is to have it tested.
Your doctor will likely test a sample of your urine for protein. Laboratory tests that measure exact amounts of protein or albumin in the urine are recommended for people at risk for kidney disease, especially those with diabetes. If laboratory tests show high levels of protein, your doctor may advise you to have your urine checked again after a week or two. You have persistent proteinuria if the second test also shows high levels of protein. Your doctor may recommend additional tests to evaluate your kidney or renal function.
Your health care provider may also test a sample of your blood for creatinine and urea nitrogen. Healthy kidneys normally remove these waste products from the blood. If tests reveal high levels of these substances in your blood, it would indicate that the kidney function is impaired.
Proteinuria can be managed by treating the underlying cause. If you have diabetes, hypertension, or both, the primary goal of treatment is to control your blood sugar and blood pressure. Diabetes and hypertension can be controlled by
- Following a healthy diet. Experts recommend restricting or limiting dietary intake of salt and proteins. A registered dietitian can help you develop and follow a healthy eating plan.
- Taking your prescribed medicines
- Getting plenty of exercise
National Kidney and Urologic Diseases Information Clearinghouse. Proteinuria. Available at http://kidney.niddk.nih.gov/kudiseases/pubs/proteinuria/index.htm
National Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD. NIH Publication No. 06-4732, September 2006. Retrieved July 3, 2008