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Oxalate, Urine, 24-hour
MessageSendout, Mayo test code: OXU
Test Code
LAB421
Alias/See Also
Oxalate
OXU
OXU
CPT Codes
83945
Preferred Specimen
4 mL from a 24-hour urine collected in 5 mL of diazolidinyl urea (Germall) as a preservative at the start of collection.
Patient Preparation
Avoid taking large doses (>2 g orally/24 hours) of vitamin C during specimen collection.
Minimum Volume
1 mL
Other Acceptable Specimens
URINE PRESERVATIVE COLLECTION OPTIONS
Note: The addition of preservative must occur at the start of collection or application of temperature controls must occur during and after collection.
| Ambient | No |
| Refrigerate | OK |
| Frozen | No |
| 50% Acetic Acid | No |
| Boric Acid | No |
| Diazolidinyl Urea | Preferred |
| 6M Hydrochloric Acid | No |
| 6M Nitric Acid | No |
| Sodium Carbonate | No |
| Thymol | No |
| Toluene | No |
Instructions
1. Add 5 mL of diazolidinyl urea (Germall) as a preservative at start of collection or refrigerate specimen during and after collection.
2. Collect urine for 24 hours.
3. Specimen pH should be between 4.5 and 8 and will stay in this range if kept refrigerated. Specimens with pH above8 indicate bacterial contamination, and testing will be cancelled. Do not attempt to adjust pH as it will adversely affect results.
2. Collect urine for 24 hours.
3. Specimen pH should be between 4.5 and 8 and will stay in this range if kept refrigerated. Specimens with pH above8 indicate bacterial contamination, and testing will be cancelled. Do not attempt to adjust pH as it will adversely affect results.
Transport Container
Plastic tube or a clean, plastic aliquot container with no metal cap or glued insert
Transport Temperature
Refrigerated
Specimen Stability
Refrigerated (preferred): 14 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Methodology
Enzymatic
FDA Status
Approved
Setup Schedule
Monday through Saturday
Report Available
3-5 days
Limitations
Ingestion of ascorbic acid (>2 g/24 hours) may falsely elevate the measured urinary oxalate excretion.
Reference Range
Included with report
Clinical Significance
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
Identifying increased urinary oxalate as a risk factor for stone formation
Diagnosis of primary or secondary hyperoxaluria
Performing Laboratory
Mayo Clinic Laboratories, Rochester, Minnesota
Additional Information
Oxalate, 24 Hour, Urine
