If a person is at risk or experiencing symptoms of kidney disease, a nephrologist will take a simple test for protein in the urine. Protein is an important building block in the body, and your kidneys normally reabsorb any filtered proteins. However, when your kidneys are damaged, protein leaks into the urine and an excess amount of protein in the urine may be an early sign of kidney damage.

How do you detect protein in the urine?

There are different tests to detect protein in the urine. If there is persistent protein in the urine (two positive tests over several weeks), this is an indication of chronic kidney disease. Another test that would be administered is a blood test to measure your level of creatinine, a waste that comes from normal muscle activity. When your kidneys are damaged, creatinine can build to high levels in your blood. The results of your creatinine blood test should be used to estimate your level of kidney function.

Proteinuria is a sign of chronic kidney disease (CKD), which can result from diabetes, high blood pressure, and diseases that cause inflammation in the kidneys. For this reason, testing for albumin in the urine is part of a routine medical assessment for everyone. Kidney disease is sometimes called renal disease. 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.

Who is at risk for proteinuria?

People with diabetes, hypertension, or certain family backgrounds are at risk for proteinuria. In the United States, diabetes is the leading cause of ESRD. In both type 1 and type 2 diabetes, albumin in the urine is one of the first signs of deteriorating kidney function. As kidney function declines, the amount of albumin in the urine increases.

Another risk factor for developing proteinuria is hypertension or high blood pressure. Proteinuria in a person with high blood pressure is an indicator of declining kidney function. If the hypertension is not controlled, the person can progress to full kidney failure.

African Americans are more likely than Caucasians to have high blood pressure and to develop kidney problems from it, even when their blood pressure is only mildly elevated. In fact, African Americans are six times more likely than Caucasians to develop hypertension-related kidney failure. Other groups at risk for proteinuria are American Indians, Hispanics/Latinos, Pacific Islander Americans, older adults, and overweight people. These at-risk groups and people who have a family history of kidney disease should have their urine tested regularly.

What are the signs and symptoms of proteinuria?

Proteinuria has no signs or symptoms in the early stages. Large amounts of protein in the urine may cause it to look foamy in the toilet. Also, because protein has left the body, the blood can no longer soak up enough fluid, so swelling in the hands, feet, abdomen, or face may occur. This swelling is called edema. These are signs of large protein loss and indicate that kidney disease has progressed. Laboratory testing is the only way to find out whether protein is in a person’s urine before extensive kidney damage occurs.