Protein in the urine, or proteinuria, is often an early sign that the kidneys are under stress. It usually causes no symptoms, yet it is one of the most important markers of kidney health. Dr. Satarupa Deb evaluates and treats proteinuria at Bombay Hospital, South Mumbai.
What Is Proteinuria?
Healthy kidneys keep useful proteins such as albumin in the blood while filtering out waste. When the kidney filters are damaged, protein leaks into the urine. Small amounts of albumin leakage are called moderately increased albuminuria (previously microalbuminuria), and larger amounts indicate more significant kidney damage.
Persistent proteinuria is linked to a higher risk of kidney disease progression and heart disease, so reducing it is a key goal of treatment.
Proteinuria is also an important warning sign for the heart and blood vessels. For this reason, doctors now check urine albumin routinely in people with diabetes, high blood pressure and chronic kidney disease, even when they feel completely well. Detecting it early gives the best opportunity to protect the kidneys.
Causes and Risk Factors
Some proteinuria is temporary, for example after fever, heavy exercise or standing for long periods. Persistent proteinuria may be caused by:
- Diabetes, a leading cause in India
- High blood pressure
- Glomerular diseases such as minimal change disease, FSGS, membranous nephropathy and IgA nephropathy
- Lupus and other autoimmune conditions
- Certain infections and medicines
- Pre-eclampsia during pregnancy
Symptoms
Mild proteinuria usually causes no symptoms and is found only on testing. When protein loss is heavy, symptoms may include:
- Frothy or foamy urine
- Swelling of the face, especially around the eyes in the morning
- Swelling of the feet, ankles or abdomen
- Weight gain from fluid retention
Diagnosis
A dipstick test may show protein, but more accurate tests are used to measure the amount and confirm that it is persistent.
- Urine albumin-to-creatinine ratio (UACR) or protein-to-creatinine ratio (UPCR) on a spot sample
- 24-hour urine protein collection in some cases
- Blood tests for creatinine, eGFR, albumin, cholesterol and blood sugar
- Tests for autoimmune disease or infection where relevant
- Kidney ultrasound and, if needed, a kidney biopsy
Treatment of Proteinuria
Treatment targets the underlying cause and aims to reduce protein leakage to protect the kidneys. Your nephrologist may recommend blood pressure medicines of the ACE inhibitor or ARB group, which lower protein loss, and in suitable patients newer kidney-protective medicines such as SGLT2 inhibitors.
Good control of diabetes and blood pressure, a lower-salt diet, weight management and stopping smoking all help. When a glomerular disease is the cause, specific treatment, sometimes including immunosuppressive medicines, may be required. Regular urine tests track your response.
When to See a Nephrologist
Consult a nephrologist if protein is found on repeated urine tests, if you have heavy protein loss or swelling, or if proteinuria appears along with blood in the urine or falling kidney function.
Frequently Asked Questions
Does frothy urine always mean protein loss?
No. Urine can froth when passed forcefully or when it is concentrated. Persistent frothy urine, especially with swelling, should be checked with a urine protein test.
Can proteinuria go away?
Temporary proteinuria from fever or exercise usually resolves by itself. Persistent proteinuria can often be reduced with treatment, and in some glomerular diseases it may go into remission.
Should I stop eating protein if I have proteinuria?
Do not cut protein drastically on your own. Very low protein intake can cause malnutrition. Your doctor or dietitian will advise a suitable, balanced protein intake for your condition.
How often should people with diabetes test for urine protein?
Guidelines recommend that people with diabetes have a urine albumin test and a blood creatinine test at least once a year, or more often if abnormalities are found.
Consult Dr. Satarupa Deb
If your urine test shows protein, book a consultation with Dr. Satarupa Deb at Bombay Hospital, South Mumbai, to understand the cause and protect your kidneys early.
This page is for general information only and is not a substitute for a medical consultation. Please consult a qualified doctor for diagnosis and treatment.