Last reviewed by Dr. Leena Joshi, MD, October 2026
Proteinuria is the presence of excess protein in the urine, often indicating kidney damage or disease. Dr. Leena Joshi, a board-certified nephrologist serving San Mateo County, performs comprehensive proteinuria workups including urine testing, blood work, and imaging studies to identify the underlying cause. Dr. Joshi develops individualized treatment plans that may include medication, dietary modifications, and management of conditions like diabetes or high blood pressure that contribute to kidney protein loss.
What is proteinuria?
Proteinuria occurs when the kidneys allow too much protein to pass into the urine instead of keeping it in the bloodstream. Healthy kidneys have tiny filters called glomeruli that keep protein and other important substances in the blood while removing waste products. When these filters become damaged or stressed, protein can leak through. Proteinuria can range from mild and temporary to severe and persistent. Some people have small amounts of protein in their urine after exercise or during illness, which usually goes away on its own. However, ongoing proteinuria often signals kidney disease or damage that requires medical attention. Dr. Joshi explains that early detection through a proteinuria workup is important because kidney problems often have no symptoms in the early stages. Finding and treating the cause can help protect kidney function over time.
Signs and symptoms
- Foamy or bubbly urine that resembles beaten egg whites
- Swelling in the hands, feet, ankles, or face
- Unexplained weight gain from fluid retention
- Fatigue or feeling unusually tired
- Loss of appetite or nausea
- Puffiness around the eyes, especially in the morning
- No symptoms at all in many cases, found only through routine testing
How Dr. Joshi manages proteinuria
Dr. Joshi begins the proteinuria workup with a thorough review of medical history and a physical examination at her San Mateo County offices. The nephrologist orders specific urine tests to measure the amount and type of protein present, including a 24-hour urine collection or a spot urine protein-to-creatinine ratio. Dr. Joshi also performs blood tests to assess kidney function, blood sugar, and cholesterol levels. Depending on initial findings, Dr. Joshi may recommend additional tests such as kidney ultrasound or, in some cases, a kidney biopsy to determine the exact cause. Treatment plans are tailored to each patient and the underlying condition. Dr. Joshi may prescribe medications such as ACE inhibitors or ARBs to reduce protein leakage and protect the kidneys. The nephrologist works closely with patients to manage contributing factors like diabetes, hypertension, or autoimmune diseases. Dr. Joshi also provides guidance on dietary changes, including sodium and protein intake adjustments when appropriate.
When to see a nephrologist for proteinuria
- Your primary care physician detects protein in your urine on routine testing
- You notice persistent foamy urine or unexplained swelling
- You have diabetes or high blood pressure and need specialized kidney monitoring
- Your protein levels remain elevated despite initial treatment
- You have a family history of kidney disease
- Your kidney function tests show declining results
Frequently asked questions
What causes protein to appear in urine?
Protein in urine can result from diabetes, high blood pressure, glomerulonephritis, lupus, or other kidney diseases. Temporary proteinuria may occur with fever, intense exercise, or dehydration. Dr. Joshi performs a complete proteinuria workup to identify the specific cause in each San Mateo County patient.
How is proteinuria diagnosed?
Dr. Joshi diagnoses proteinuria through urine tests that measure protein levels, including dipstick tests, 24-hour urine collections, or spot urine samples. Blood tests assess kidney function. Additional testing may include imaging studies or kidney biopsy depending on initial findings.
Can proteinuria be reversed?
Some cases of proteinuria can improve or resolve with treatment, especially when caught early. Dr. Joshi focuses on treating underlying causes and protecting remaining kidney function. The outcome depends on the specific cause and how quickly treatment begins.
Is proteinuria always a sign of kidney disease?
Not always. Temporary proteinuria can occur with fever, stress, or strenuous exercise and resolves on its own. However, persistent proteinuria often indicates kidney damage. Dr. Joshi determines whether proteinuria requires treatment through comprehensive testing at her San Mateo County practice.
What medications treat proteinuria?
Dr. Joshi may prescribe ACE inhibitors or angiotensin receptor blockers (ARBs) to reduce protein leakage and protect kidneys. Other medications target underlying conditions like diabetes or high cholesterol. Your nephrologist will determine the most appropriate treatment based on your specific diagnosis.
How often should proteinuria be monitored?
Monitoring frequency depends on the severity and cause of proteinuria. Dr. Joshi typically schedules follow-up visits every few months for patients with persistent proteinuria. More frequent monitoring may be necessary if kidney function is declining or treatment plans change.
Dr. Leena Joshi provides comprehensive proteinuria workup and treatment at two convenient San Mateo County locations: 1750 El Camino Real Suite 301 in Burlingame and 1800 Sullivan Avenue Suite 507 in Daly City. Call (650) 355-5551 to schedule a consultation with a board-certified nephrologist who specializes in kidney disease diagnosis and management.
This page is for general education and is not a substitute for medical advice. Always consult your physician about your specific situation.
Medically reviewed by Leena Joshi, MD.