Proteinuria
Background
- Normal protein excretion 150mg/24 hours or 10mg/100mL
- >3.5g/24h considered nephrotic range
- Dipstick: more sensitive to albumin, less sensitive to Bence-Jones protein and globulins
- "Trace" protein ≈ 10mg/100mL (i.e. upper limit of normal)
Causes/Differential Diagnosis
Functional
- Benign: fever/acute illness, cold exposure, orthostatic proteinuria, strenuous exercise, hypertension
- CHF, shock
- Preeclampsia/eclampsia/HELLP, [[acute fatty liver of pregnancy
Renal
- Tubular dysfunction
- Glomerular disease (e.g. glomerulonephritis, diabetes, HIV, SLE, amyloidosis, IgA nephropathy or membranous nephropathy)
- Nephrotic syndrome
- Pyelonephritis
- Malignant hypertension
- Alport syndrome
Drugs
- Aminoglycosides, [[penicillin]s, amphotericin, penicillamine, deferasirox
- NSAIDs, gold
- Chloral hydrate toxicity
- Lead toxicity
Protein overload
Note: bence-jones globulins NOT detected on dipstick
Other
- Gout
- Hypokalemia, Cushing's syndrome
- Electrocution
- Polycystic kidney disease
- Hepatorenal syndrome
- Leptospirosis
- Polyarteritis nodosa
- Serum sickness
- Scleroderma
False Positives
- Menses or other vaginal bleeding
- Highly concentrated urine
- Alkaline urine
- Acetazolamide, cephalosporins, bicarbonate