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HelpTest Code LAB421 Oxalate, 24 Hour, Urine
Additional Codes
OXAL U QNT
Reporting Name
Oxalate, 24 Hr, USCH Clinical System Name: Urine Oxalate Quantitation, 24 Hours
Useful For
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
Necessary Information
Twenty-four hour volume is required.
Specimen Required
Patient Preparation: Avoid taking large doses (>2 g orally/24 hours) of vitamin C during specimen collection.
Supplies:
-Diazolidinyl Urea (Germall) 5.0 mL (T822)
-Sarstedt Aliquot Tube, 5mL (T914)
Container/Tube: Plastic tube or a clean, plastic aliquot container with no metal cap or glued insert
Specimen Volume: 4 mL
Collection 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.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Specimen Type
UrineSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated | 14 days |
Day(s) Performed
Monday through Saturday
TAT: 5 - 7 days
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Method Name
Enzymatic
Method Description
The assay utilizes oxalate oxidase, which oxidizes oxalate to carbon dioxide and peroxide. In the presence of peroxidase, the peroxide oxidatively couples 3-methyl-2-benzothiazolinone and 3-dimethylaminobenzoic acid to form indamine dye, which is measured spectrophotometrically at 600 nm.(Kasidas GP, Rose GA: Continuous-flow assay for urinary oxalate using immobilized oxalate oxidase. Ann Clin Biochem 1985;22:412-419; package insert: Oxalate kit. Trinity Biotech; V 11/2017)
Reference Values
0.11-0.46 mmol/24 h
9.7-40.5 mg/24 h
The reference value is for a 24-hour collection. Specimens collected for other than a 24-hour time period are reported in unit of mmol/L for which reference values are not established.
Reference values have not been established for patients who are younger than 16 years of age.
Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
83945
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| OXU | Oxalate, 24 Hr, U | 14862-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| OCATE | Oxalate, 24 Hr, U (mmol/24 hr) | 14862-7 |
| OXU1 | Oxalate, 24 Hr, U (mg/24 hr) | 2701-1 |
| TM17 | Collection Duration | 13362-9 |
| VL15 | Urine Volume | 3167-4 |
Special Instructions
Testing Algorithm
Report Available
3 to 5 daysReject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
Aliases: Oxalate