24-hour urine protein

What it measures

Measures the total protein lost in urine over a full day. It quantifies proteinuria in kidney disease and pre-eclampsia, though spot ratios are often used instead.

Specimen and preparation

• Specimen: 24-hour urine collection
• Tube: Urine top
• Preparation: Discard first morning void, then collect all urine for 24 h including next morning's first void; keep cool and record total volume.

Reference range

Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.

Causes of high values

• Glomerular disease (> 3.5 g/24 h: nephrotic range)
• Pre-eclampsia (≥ 300 mg/24 h)
• Diabetic and hypertensive nephropathy
• Multiple myeloma (light chains)
• Fever, heavy exercise (transient)

Method

Turbidimetry (benzethonium chloride) or pyrogallol red dye binding

Good to know

Check completeness with 24-h urine creatinine; spot urine protein/creatinine ratio correlates well.

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