Oxalate, Plasma

Test Code

39756

CPT Codes
83945<br>Limited Access Code

Preferred Specimen

5 mL acidified plasma collected in sodium heparin (green-top) tube

Patient Preparation
1. Fasting (12 hours)
2. Patient should avoid taking vitamin C supplements for 24 hours prior to collection

Minimum Volume

2 mL

Instructions

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

1. Place specimen on wet ice immediately.
2. Centrifuge for 10 minutes at 3,500 rpm at 4° C within 1 hour of collection.
3. Aliquot plasma into a plastic vial.
4. Adjust the pH of the plasma specimen to a pH of 2.3-2.7 with approximately 10 mcL concentrated (12M) hydrochloric acid (or 20 mcL of 6M HCl) per 1 mL plasma.

Additional Information: Nonacidified specimens can be accepted if the heparinized plasma is properly frozen. However, a disclaimer will be added in nonacidified plasma: Sample was received nonacidified and frozen. In nonacidified samples oxalate values may increase spontaneously.

Transport Container

Plastic vial

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

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

Methodology
Enzymatic

Setup Schedule

Set up: Mon-Fri; Report available: 3 days

Reference Range

≤ 2.0 mcmol/L

Reference values have not been established for patients under 18 years old or greater than 87 years of age

Clinical Significance

Assessing the body pool size of oxalate in patients with enzyme deficiencies, such as primary hyperoxaluria (PH), or patients with enteric hyperoxaluria (EH) Aiding in the diagnosis of PH in a patient with chronic kidney disease (CKD) of indeterminate cause when urinary oxalate is not available Monitoring patients with renal failure and primary or enteric
hyperoxaluria in order to be sure they are receiving enough dialysis Aiding in maintaining plasma oxalate levels below supersaturation (25-30 mcmol/L).

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.