Protein in the urine — known medically as proteinuria or albuminuria — occurs when the kidneys improperly spill protein in the urine. This can be normal if it occurs with exercise or fever, or it can be a sign of kidney disease.
One of the primary functions of the kidney is to remove excess fluid and waste from the blood, which then flows into the bladder as urine. The kidney works by keeping normal electrolytes in the blood, while allowing waste products to flow in the urine. When the kidney allows protein to flow into the urine instead of staying in the blood, proteinuria can develop. Proteinuria can be normal if due to gravity, exercise or fevers, or it can be a sign of kidney disease.
People are at greater risk of kidney disease if they have:
Reduced kidney function can also be the result of:
- Anomalies of the kidneys or urinary tract at birth
- Damage to the kidneys as a result of illness, extreme dehydration, toxins or immune system disorders (acute kidney injury)
There are usually no physical symptoms of protein in the urine at low levels. At this stage the problem is typically detected in a urine test.
Proteinuria at high levels may be noticed as:
- Foamy, frothy or bubbly urine
- Swelling of the hands, feet, abdomen or face
- Shortness of breath
Proteinuria is detected and diagnosed with a urine test to measure the levels of protein in the urine.
Because proteinuria has no physical symptoms at low levels, and because it can sometimes be associated with kidney disease, regular urine tests are recommended if you or your child are at higher risk for kidney problems.
When a test measures an abnormally high level of protein in the urine, that single test is not considered a definitive indication of proteinuria or kidney problems. Protein levels in urine can rise after intense exercise or as a result of illness or dehydration. A positive test will be followed by additional urine tests to confirm the result, especially urine tests done first thing in the morning to make sure gravity is not causing the protein, which is normal (orthostatic proteinuria).
When high levels of protein are found in urine, additional tests are usually done to more carefully analyze kidney problems and understand their cause. These may include:
- Blood tests to estimate the kidneys’ function (glomerular filtration rate or GRF)
- Ultrasound, CT scan or MRI of the kidneys and urinary tract
- Kidney biopsy
When proteinuria or kidney disease are detected, treatment focuses on addressing the cause of the kidney problems.
If diabetes or high blood pressure are causing or contributing to kidney problems, the goal of treatment will be to get these conditions under control to prevent further kidney damage. Treatment may include:
- Lifestyle changes to improve diet, increase healthy exercise or lose weight
- Medications (insulin for diabetes, ACE inhibitors or ARBs for hypertension)
When proteinuria is not detected early or when treatment is unable to prevent serious damage to the kidneys, kidney failure may require treatment with:
In cases of acute kidney injury, treatment to address the cause of short-term kidney damage may result in full or significant recovery of kidney function.
In cases of chronic kidney disease, the goal of treatment is to prevent further kidney damage.
When kidney function falls to levels that cause serious health problems, dialysis and kidney transplantation may be needed.
Anyone diagnosed with proteinuria should have regular urine tests and exams, even after the problem is identified and the causes addressed, to watch for any return of kidney problems or worsening of kidney function.
The Division of Nephrology at Children's Hospital of Philadelphia (CHOP) provides your child with world-class care for and treatment of kidney diseases. Our division is consistently ranked as one of the top programs in the nation by U.S. News & World Report. Our physicians and staff are known for their ability to diagnose, treat and care for children with all forms of kidney disease. Here, you'll find superb clinical care and an equal measure of understanding and compassion. We have experts who focus on the evaluation and treatment of children with protein in the urine and associated chronic kidney disease (glomerulonephritis or nephrotic syndrome).
Our multidisciplinary team — including nephrologists, clinical nurse specialists, social workers, a pharmacist, psychologist, and nutritionist — provides comprehensive medical consultations and evaluations for children with renal diseases, electrolyte disorders and hypertension.
Reviewed by: Benjamin Laskin, MD