Test Details
Mnemonic
OXA
Ordering Code
3508310
CPT-4 Code(s)
83945
Specimen Information
Patient Preparation
Patient should be fasting for at least 12 hours prior to collection. Patient should avoid taking
vitamin C supplements for 24 hours prior to collection.
vitamin C supplements for 24 hours prior to collection.
Collect
Green sodium heparin
Specimen Preparation
After drawing specimen, immediately place green sodium heparin tube on wet ice. Centrifuge
for 10 minutes 3500 rpm within 1 hour of collection. Use of a 4 degree °C refrigerated centrifuge
is optimal but not required. Aliquot 5.0 mL plasma in screw capped plastic vial. 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. CRITICAL FROZEN.
for 10 minutes 3500 rpm within 1 hour of collection. Use of a 4 degree °C refrigerated centrifuge
is optimal but not required. Aliquot 5.0 mL plasma in screw capped plastic vial. 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. CRITICAL FROZEN.
Alternate Specimen
Nonacidified specimens can be accepted if the heparinized plasma is properly frozen. A
disclaimer will be added in nonacidified plasma, "Sample was received nonacidified and frozen.
In nonacidified samples oxalate values may increase spontaneously." Although there can be a
small absolute increase of plasma oxalate in nonacidified specimens, this will not change the
clinical interpretation.
Rejection Criteria
disclaimer will be added in nonacidified plasma, "Sample was received nonacidified and frozen.
In nonacidified samples oxalate values may increase spontaneously." Although there can be a
small absolute increase of plasma oxalate in nonacidified specimens, this will not change the
clinical interpretation.
Rejection Criteria
Minimum Volume
2.0 mL
Transport Temperature
Critical frozen
Rejection Criteria
Sample collected in anything other than a green sodium heparin.
Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days
Refrigerated: Unacceptable
Frozen: 30 days
Methodology
Enzymatic
Reference Range
≤ 2.0 mcmol/L
Reference values have not been established for patients younger than 18 years of age or older
than 87 years of age.
Reference values have not been established for patients younger than 18 years of age or older
than 87 years of age.
Performing Laboratory
MAYO
New York DOH Approval Status
Yes