A 24-hour urine oxalate test measures the total oxalate excreted in urine over one day to assess risk of calcium oxalate kidney stones, detect hyperoxaluria, and monitor therapy. The patient collects all urine for 24 hours in a provided container (store refrigerated or with preservative per instructions). Elevated results suggest increased oxalate production or absorption and guide dietary, medical, or genetic evaluation.

A 24‑hour urine test does not directly detect an existing kidney stone — imaging (CT, ultrasound, X‑ray) is used for diagnosis. The test measures urine volume and levels of calcium, oxalate, uric acid, citrate, sodium and other substances to identify metabolic risk factors for stone formation. It’s useful after a stone episode or for recurrent stones to guide prevention and treatment.

High oxalate in urine means excess oxalate excretion, increasing risk of calcium‑oxalate kidney stones. Causes include high dietary oxalate, excess vitamin C, intestinal malabsorption, certain medications, or rare genetic overproduction. Evaluation commonly uses a 24‑hour urine test and metabolic assessment. Management emphasizes good hydration, moderate dietary oxalate reduction, adequate dietary calcium, and treating underlying conditions to lower stone risk.

Normal 24‑hour urine results: volume 800–2,000 mL; creatinine roughly 0.6–2.6 g/day (varies by sex/muscle mass); total protein <150 mg/day and albumin <30 mg/day (no microalbuminuria); calcium about 100–300 mg/day; sodium varies with diet (typical 40–220 mmol/day); uric acid within expected sex-based ranges; no detectable glucose, significant blood, or ketones.

Lower urinary oxalate by drinking plenty of water to dilute urine, following a low-oxalate diet (avoid spinach, nuts, cocoa, tea, beets), and eating adequate dietary calcium with meals to bind oxalate in the gut. Limit high‑dose vitamin C, excessive sodium and animal protein. Consider probiotics or prescribed medications for enteric or primary hyperoxaluria. Discuss testing and tailored treatment with your healthcare provider.

Before a 24-hour urine collection, avoid foods and drinks that can alter results: caffeine (coffee, tea, cola), chocolate, bananas, vanilla‑flavored products, citrus fruits, strong cheeses, alcoholic drinks, and large doses of vitamin C. Also avoid smoking and certain medications if advised. Specific restrictions depend on the test type—follow your clinician’s or lab’s instructions.