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

Renal

• Tubular dysfunction
• Glomerular disease (e.g. glomerulonephritis, diabetes, HIV, SLE, amyloid, IgA or membranous nephropathy)
• Nephrotic syndrome
• Pyelonephritis
• Malignant hypertension

Drugs

• Aminoglycosides, [[penicillin]s, amphotericin
• NSAIDs, gold

Protein overload

Note: bence-jones globulins NOT detected on dipstick

• Multiple myeloma, lymphoma, leukemia
• Rhabdomyolysis

Other

• Gout
• Hypokalemia, Cushing's syndrome
• Electrocution
• Polycystic kidney disease

False Positives

• Menses or other vaginal bleeding
• Highly concentrated urine
• Alkaline urine
• Acetazolamide, cephalosporins, bicarb

See Also

• Urine analysis