Oxalate, Plasma
Use
Assessing the body pool size of oxalate in patients with enzyme deficiencies, such as primary hyperoxaluria (PH), or patients with enteric hyperoxaluria; aiding in the diagnosis of PH in a patient with chronic kidney disease of indeterminate cause when urinary oxalate is not available; monitoring patients with renal failure and primary or enteric hyperoxaluria to ensure sufficient dialysis; and aiding in maintaining plasma oxalate levels below supersaturation (25–30 μmol/L).
Special Instructions
Testing algorithm: See Hyperoxaluria Diagnostic Algorithm. Method Name: Enzymatic. NY State Available: Yes. Reporting Name: Oxalate, Plasma. Aliases: Oxalate.
Limitations
Proper specimen processing and acidification are essential; non‑acidified specimens can be accepted if heparinized plasma is properly frozen, but a disclaimer will be added; non‑acidified samples may demonstrate spontaneous oxalate increase, potentially by up to 50%. High levels of ascorbic acid (vitamin C) interfere with testing; therefore, vitamin C supplements should be avoided prior to specimen collection.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 15085-4
- 15085-4
Result Turnaround Time
3-7 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
5 mL
Minimum Volume
2 mL
Container
Green top (sodium heparin) tube; plastic vial
Collection Instructions
Fasting 12 hours preferred but not required; no vitamin C supplements for 24 hours prior; immediately place on wet ice; centrifuge within 1 hour (10 minutes at 3500 rpm, refrigerated if possible); aliquot plasma into plastic vial; adjust pH to 2.3–2.7 using ~10 μL 12M HCl or 20 μL 6M HCl per 1 mL plasma.
Patient Preparation
Fast 12 hours preferred; avoid vitamin C supplements for 24 hours prior.
Causes for Rejection
All specimens will be evaluated for suitability; nonacidified specimens may affect results.
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | Frozen: stable for 30 days |