POXA - Specimen: Oxalate, Plasma

Test Catalog

Test Name

Test ID: POXA    
Oxalate, Plasma

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

See Hyperoxaluria Diagnostic Algorithm in Special Instructions.

Specimen Type Describes the specimen type validated for testing

Plasma Na Heparin

Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.

Any client who has never drawn a specimen for this test should call 800-533-1710 or 507-266-5700 and ask for the Renal Laboratory for more detailed instructions.


Patient Preparation:

1. Fasting (12 hours)

2. Patient should avoid taking vitamin C supplements for 24 hours prior to draw.

Specimen Type: Acidified plasma

Collection Container/Tube: Green top (sodium heparin)

Submission Container/Tube: Plastic vial

Specimen Volume: 5 mL

Collection Instructions:

1. Place on wet ice immediately.

2. Centrifuge for 10 minutes at 3,500 rpm at 4 degrees C within 1 hour of draw.

3. Adjust the pH of the plasma specimen to a pH of 1 to 3.5 (ideal range is 2.3-2.7) with approximately 10 mcL concentrated (12N) HCl per 1 mL plasma.

Additional Information: Nonacidified specimen can be accepted if the heparinized plasma is properly frozen. However, a disclaimer will be added in nonacidified plasma, oxalate values may increase spontaneously (average 50% increase for plasma oxalate <15 mcmol/L; average 10% increase for plasma oxalate >15 mcmol/L).

Specimen Minimum Volume The amount of sample necessary to provide a clinically relevant result as determined by the Laboratory.

2 mL

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected








Nonheparinized specimen

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperatures are also included.

Specimen TypeTemperatureTime
Plasma Na HeparinFrozen14 days