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Test Code LAB421 Oxalate, 24 Hour, Urine

Additional Codes

OXAL U QNT

Reporting Name

Oxalate, 24 Hr, U
Seattle Children's Hospital Note:

SCH 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

Urine

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated 14 days

Day(s) Performed

Monday through Saturday

Seattle Children's Hospital Note:

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

Testing Algorithm

See Hyperoxaluria Diagnostic Algorithm

Report Available

3 to 5 days

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

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

Forms

If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.

Seattle Children's Hospital Additional Information:

Aliases: Oxalate