Test Directory

Useful for monitoring therapy for kidney stones using 24-hour urine collections, identifying increased urinary oxalate as a risk factor for stone formation, and diagnosing primary or secondary hyperoxaluria.

Specimen Type: 24 Hour Urine

Collection Container: 24 Hour Plastic Urine Container

Desired Specimen Volume: 4 mL

1. Collect 24-hour urine.
2. Specimen must be maintained refrigerated during and after collection.
3. 24-hour volume (in milliliters) is required.

1. Mix container thoroughly and transfer 4 mL of urine to a clear aliquot tube (screw cap).
2. Specimen pH should be between 4.5 and 8 and will stay in this range if kept refrigerated. Specimens with pH above 8 indicate bacterial contamination, and testing will be canceled. 
3. Do not attempt to adjust pH, as it will adversely affect results.

For 24 hours before, as well as during the collection process, patient should not take large doses (>2 g orally/24 hours) of vitamin C.

Transport to the laboratory refrigerated.

 See patient report.

Ingestion of ascorbic acid (>2 g/24 hours) may falsely elevate the measured urinary oxalate excretion.

• Oxalate, 24 Hour, Urine