Oxalate

Alternate test name

Oxalic acid, plasma

Lab area

Clinical Biochemistry - Metabolic Diseases

Method and equipment

Stable isotope dilution Gas Chromatography - Mass Spectrometry (GC-MS)

Expected turn-around time

3 weeks

Specimen type

Plasma

Specimen requirements

1 mL acidified plasma collected in a Green Top Lithium Heparin tube only. See special requirements for processing instructions.

Storage and transportation

Store at -20°C and transport frozen on dry ice.

Special requirements

Patient should be fasting for a minimum of 12 hours and should avoid taking Vitamin C supplements for 24 hours prior to the draw.
Collect specimen and place immediately on wet ice.
Complete the following steps within 30 minutes from time of collection.
- Centrifuge for 10 minutes at 2,000 rpm in a refrigerated centrifuge (4°C).
- Remove the plasma to a clean plastic vial.
- Add 20 µL of concentrated HCl for every 1 mL of plasma. Cap and vortex-mix the tube. Final pH on plasma should fall between 1 to 3.5 and should be written on the tube.
- Freeze immediately and store @ -20°C

Shipping information

The Hospital for Sick Children

Rapid Response Laboratory

555 University Avenue, Room 3642

Toronto, ON

Canada

M5G 1X8

Phone: 416-813-7200

Toll Free: 1-855-381-3212

Hours: 7 days/week, 24 hours/day

Requisition

Oxalate - requisition

Background and clinical significance

This test is useful for the monitoring of kidney function for patients with hyperoxaluria, a condition that may result in kidney stone formation, nephrocalcinosis, progressive kidney damage and systemic calcium oxalate deposition.

Disease condition