Protein Test in Urine (Proteinuria)
A urine protein test measures the concentration of protein in urine. Normally, kidneys filter waste products while retaining proteins such as albumin in the blood. Proteinuria, it may signal kidney damage or other health problems. Protein concentration in urine is usually reported in grams per liter (g/L) or milligrams per deciliter (mg/dL). For 24‑hour urine collections, results are expressed as grams per 24 hours (g/24 h).
Reference ranges
- Spot urine sample: < 0.15 g/L (150 mg/L)
- 24‑hour urine collection: < 0.15 g/24 h
- Albumin-to-creatinine ratio (ACR): < 3 mg/mmol
Monitoring helps track progression in patients with diabetes, hypertension, or chronic kidney disease. Proteinuria can be the first sign of kidney disease. Diagnosis Identifies causes such as infections, autoimmune disorders, or cardiovascular disease.
Indications for the test include; diabetes mellitus (risk of diabetic nephropathy), high blood pressure, family history of kidney disease and people experiencing swelling (edema), foamy urine, or unexplained fatigue.
The test is done with a random urine sample, a quick test, often used for screening; 24‑hour urine collection which measures total protein excretion over a day; Albumin-to-creatinine ratio (ACR), a more precise test that adjusts for urine concentration.
Interpretation of Results
| Result | Value | Possible Meaning |
|---|---|---|
| Normal | < 0.15 g/L or < 0.15 g/24 h | Healthy kidney function |
| Mild proteinuria | 0.15–0.5 g/24 h | Early kidney stress, hypertension, diabetes |
| Moderate proteinuria | 0.5–3.0 g/24 h | Chronic kidney disease, glomerulonephritis |
| Severe proteinuria | > 3.0 g/24 h | Nephrotic syndrome, advanced kidney damage |
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