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HelpEpic Test Code LAB484 Oxcarbazepine Metabolite, Serum
Additional Codes
MML Code: OMHC
LIS Code: OXCZP
NY State Approved
YesPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Oxcarbazepine Metabolite (MHC), SMethod Name
High-Turbulence Liquid Chromatography Mass Spectrometry (HTLC-MS/MS)
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 28 days | |
| Ambient | 28 days | ||
| Frozen | 28 days |
Specimen Required
Supplies: Sarstedt Aliquot Tube 5 mL (T914)
Collection Container/Tube: Red top (serum gel/SST is not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Collect specimen immediately before next scheduled dose.
2. Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.
Specimen Type
Serum RedSpecimen Minimum Volume
0.5 mL
Reference Values
Oxcarbazepine metabolite: 10-35 mcg/mL
Report Available
1 to 3 daysDay(s) Performed
Monday through Saturday
CPT Code Information
80183
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Useful For
Monitoring serum concentration during oxcarbazepine therapy
Assessing compliance
Assessing potential toxicity
Clinical Information
Oxcarbazepine (OCBZ) is approved as monotherapy and adjunctive therapy for partial seizures with and without secondary generalized seizures in adults and as adjunctive therapy for partial seizures in children. In humans, OCBZ is a prodrug that is almost immediately and completely metabolized to 10-hydroxy-10,11-dihydrocarbamazepine, known as monohydroxy carbamazepine (MHC), an active metabolite that is responsible for OCBZ's therapeutic effect. The elimination half-life is approximately 2 hours for OCBZ and 7 to 11 hours for MHC. The therapeutic range (10-35 mcg/mL) is based on concentrations of the metabolite, not the parent drug; this assay measures the metabolite only.
In clinical practice, the OCBZ dosage should be individually adjusted for each patient to achieve the desired therapeutic response. Toxicity associated with OCBZ includes hyponatremia, dizziness, somnolence, diplopia, fatigue, nausea, vomiting, ataxia, abnormal vision, abdominal pain, tremor, dyspepsia, and abnormal gait. These toxicities may be observed when blood concentrations are in the therapeutic range.
Interpretation
Therapeutic ranges are based on specimens collected at trough (ie, immediately before the next dose). Most individuals display optimal response to oxcarbazepine therapy when serum levels of the metabolite (measured in this assay) are between 10 and 35 mcg/mL. Some individuals may respond well outside of this range or may display toxicity within the therapeutic range. Thus, interpretation should include clinical evaluation.
Cautions
Toxic levels have not been well established.
This test cannot be performed on whole blood. Serum must be separated from cells within 2 hours of collection.
Specimen Retention Time
14 daysForms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-Neurology Specialty Testing Client Test Request (T732)
-Therapeutics Test Request (T831)