Urine Protein (Dipstick)
Urine Protein· also: Proteinuria, UP
Clinical Overview
Urine dipstick protein detects protein (primarily albumin) in the urine. The healthy kidney filters blood through glomeruli that prevent large proteins from passing into urine. Protein in urine (proteinuria) indicates glomerular damage, tubular dysfunction, or overflow proteinuria. It is one of the most important markers for kidney disease and a major risk factor for both kidney disease progression and cardiovascular disease.
Why This Test Matters
Persistent proteinuria (positive on at least 2 of 3 tests over 3 months) is a defining criterion for Chronic Kidney Disease (CKD). The dipstick primarily detects albumin — it is less sensitive to non-albumin proteins (Bence Jones proteins from myeloma, tubular proteins). Any persistent dipstick proteinuria (1+ or greater) requires quantification with albumin-to-creatinine ratio (ACR) or 24-hour urine protein. Nephrotic-range proteinuria (>3.5 g/day) causes edema, hypoalbuminemia, and hyperlipidemia. Proteinuria in diabetic patients (even microalbuminuria — detectable only by ACR, not dipstick) is an early sign of diabetic nephropathy and should trigger aggressive blood pressure and blood sugar control.
Reference RangesWHO/IFCC standards
| Reference Range | Unit | Notes |
|---|---|---|
| Negative / Non-reactive | qualitative | Negative to trace (<150 mg/day total protein) |
Also reported in: mg/dL.
What Causes Abnormal Results?
High Urine Protein Causes
- Diabetic nephropathy (most common cause of CKD globally)
- Hypertensive nephrosclerosis
- Glomerulonephritis (IgA nephropathy, lupus nephritis, FSGS, membranous nephropathy)
- Nephrotic syndrome (massive proteinuria >3.5 g/day)
- Orthostatic proteinuria (benign — protein appears when standing, clears when lying down)
- Transient proteinuria: fever, strenuous exercise, dehydration, heart failure (all reversible)
- Pre-eclampsia in pregnancy
- Myeloma kidney (overflow of Bence Jones protein — not detected by dipstick)
Low Urine Protein Causes
- Dipstick protein is negative in normal kidney function
- Dipstick misses small proteins — Bence Jones protein and tubular proteins require specific urine protein electrophoresis
Signs & Symptoms to Watch For
How to Prepare for This Test
A fresh midstream urine sample is needed. Avoid testing during or immediately after vigorous exercise (can cause transient proteinuria). Women should not be menstruating during collection (blood contamination). Any positive dipstick result should be confirmed on a repeat sample and quantified with ACR.
Factors That Can Affect Results
- Concentrated urine (high specific gravity) can cause false-positive trace proteinuria — dilute urine gives false-negative
- Highly alkaline urine (pH >8.5) causes false-positive dipstick protein
- Pyuria (pus in urine) can produce false-positive protein
- Quaternary ammonium compounds (some antiseptics) contaminate samples and cause false-positive
- Dipstick is specific for albumin — does not detect Bence Jones proteins or tubular proteins
Related Topics
Frequently Asked Questions
I had trace protein on my urine dipstick — should I be worried?
Trace protein on a single dipstick result is very commonly a transient finding with many benign causes (dehydration, exercise, fever, concentrated urine, or orthostatic proteinuria). A single trace result in an otherwise healthy person without diabetes or hypertension requires repeat testing rather than immediate concern. If trace or 1+ protein persists on two or more repeat tests over 3 months, it warrants further evaluation with an albumin-to-creatinine ratio (ACR) and kidney function tests (eGFR, creatinine). Persistent proteinuria is a key marker of kidney disease.
My diabetic patient has negative urine protein on dipstick — is their kidney function OK?
Not necessarily. The dipstick detects albumin at concentrations above approximately 150–300 mg/L — it misses the early stage of diabetic kidney disease. Microalbuminuria (20–200 mg/day of albumin, or ACR 30–300 mg/g) is the earliest detectable sign of diabetic nephropathy and is invisible to the standard dipstick. All diabetic patients should have an annual albumin-to-creatinine ratio (ACR) test, regardless of dipstick results. Early microalbuminuria is fully reversible with tight glycemic control, blood pressure management (especially with ACE inhibitors or ARBs), and SGLT-2 inhibitors.