Oxalate, 24 Hour, Urine
Use
Monitoring therapy for kidney stones using 24‑hour urine collections; identifying increased urinary oxalate as a risk factor for stone formation; diagnosis of primary or secondary hyperoxaluria.
Special Instructions
A 24‑hour urine volume in milliliters is required. Patient should not take large doses (>2 g orally/24 hours) of vitamin C for 24 hours before and during collection. Use of preservative (5 mL diazolidinyl urea/Germall) at the start of collection or refrigeration during and after collection is required. Specimen pH should be between 4.5 and 8; above 8 indicates bacterial contamination and test will be canceled.
Limitations
Ingestion of ascorbic acid (>2 g/24 hours) may falsely elevate measured urinary oxalate. Specimens with pH above 8 suggest bacterial contamination and will be canceled; do not adjust pH as it adversely affects results.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 14862-7
- 14862-7
- 2701-1
- 13362-9
- 3167-4
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
4 mL
Minimum Volume
1 mL
Container
Plastic tube or a clean, plastic aliquot container with no metal cap or glued insert
Collection Instructions
Add 5 mL of diazolidinyl urea as preservative at start or refrigerate specimen during and after collection; collect urine for 24 hours; mix container thoroughly and aliquot urine into plastic vial.
Patient Preparation
Should not take large doses (>2 g orally/24 hours) of vitamin C for 24 hours before and during collection.
Causes for Rejection
Specimens with pH above 8 indicate bacterial contamination and testing will be canceled.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 14 days |
| Frozen | 14 days |