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HelpTEST ID OMHC Oxcarbazepine Metabolite, Serum
Reporting Name
Oxcarbazepine Metabolite (MHC), SSpecimen Type
Serum RedSpecimen 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 Serum
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 Minimum Volume
Serum: 0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Refrigerated (preferred) | 28 days |
| Ambient | 28 days | |
| Frozen | 28 days |
Method Name
High-Turbulence Liquid Chromatography Mass Spectrometry (HTLC-MS/MS)
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
Oxcarbazepine metabolite: 10-35 mcg/mL
Day(s) Performed
Monday through Saturday
Report Available
1 to 3 daysSpecimen Retention Time
14 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
80183
Forms
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)
Useful For
Monitoring serum concentration during oxcarbazepine therapy or eslicarbazepine acetate (S-licarbazepine) 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.