Laboratory: Clinical Biochemistry
Test Name:
OXCARBAZEPINE METABOLITE - (S)
Test Code: MISC
Clinical Information:
Oxcarbazepine is used for treatment of seizures.  It is rapidly metabolized to 10-hydroxy-10,11-dihydrocarbamazepine, (monohydroxycarbamazepine (MHC)), an active metabolite that is responsible for the therapeutic effect. The elimination half-life is 1 to 2.5 hours for oxcarbazepine and 8 to 10 hours for MHC. The therapeutic range is based on concentrations of the metabolite, not the parent drug; this assay measures the metabolite only.
Therapeutic ranges are based on specimens drawn 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 3 and 35 μg/mL. Some individuals may respond well outside of this range, or may display toxicity within the therapeutic range. Thus, interpretation should include clinical evaluation.
Toxic levels have not been well established.
Collection Devices:
Specimen Required:


Serum: 1.0 mL
Pediatric Serum: 0.5 mL

Blood samples should be obtained at steady state prior to dose (trough).
Draw specimen immediately before next scheduled dose.
Centrifuge and aliquot within 2 hours of collecton.
 
Referral:
Plasma: 0.5 mL

Serum: 1.0 mL
Ship serum at ambient temperature, or refrigerated, or frozen.
Requisition:
Reference Values:
Oxcarbazepine metabolite (trough): 3-35 μg/mL
Availability:
Within 2 Weeks
See Also:
More Information:
Ship ambient, refrigerated or frozen to Mayo Medical Laboratories.