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Test Code DOXA1 Oxalate Analysis, Hemodialysate

Reporting Name

Oxalate, Dialysate Fluid

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Determining the amount of oxalate removed during a dialysis session


Individualizing the dialysis prescription of hyperoxaluric patients

Method Name


Specimen Required

Specimen Type: Dialysate fluid

Patient Preparation: Patient should avoid taking vitamin C supplements for 24 hours prior to dialysis

Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL urine tube or a clean, plastic aliquot container with no metal cap or glued insert

Specimen Volume: 5 mL

Collection Instructions: Adjust the pH of the specimen to 2.5 to 3.0 with 6M Hydrochloric Acid

Additional Information: Nonacidified frozen hemodialysate delivered to the laboratory within 3 days from collection will be accepted and the following comment will be added to the result: In nonacidified hemodialysate stored frozen, oxalate values may increase spontaneously.

Specimen Type

Dialysate Fluid

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Dialysate Fluid Frozen 14 days

Reject Due To

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

Reference Values

Not applicable


An exponential decrease in oxalate signal is expected through dialysis procedure.


Signals below 2 mcM at any point during dialysis suggest that the plasma has been effectively cleared, although there can be rebound after dialysis ceases.


Total oxalate removed during a dialysis session can be estimated by multiplying the concentration of oxalate in the dialysate by the oxalate flow rate for each time period that the oxalate is measured.

Day(s) and Time(s) Performed

Monday through Friday; 7:30 a.m.-5 p.m.

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 U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
DOXA1 Oxalate, Dialysate Fluid 47715-8


Result ID Test Result Name Result LOINC Value
DOXA1 Oxalate, Dialysate Fluid 47715-8


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