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| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Oxcarbazepine Metabolite
Test CodeOXCARB
Quest Code
36637
CPT Codes
80183
Includes
10-Hydroxycarbazepine
Preferred Specimen
1 mL plasma or serum
Minimum Volume
0.25 mL
Other Acceptable Specimens
Plasma collected in: EDTA (lavender-top) tube
Transport Container
Lavender-top or SST
Transport Temperature
Refrigerated, stable 2 weeks
Specimen Stability
Room temperature: 72 hours
Refrigerated: 14 days
Frozen: 60 days
Refrigerated: 14 days
Frozen: 60 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Serum Separator Tube (SST®)
Methodology
Liquid Chromatography/Tandem Mass Spectrometry
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Set up: Mon-Sat p.m.; Report available: 1-3 days
Reference Range
Therapeutic: 8.0-35.0 mcg/mL
Toxic: > 35.0 mcg/mL
Detection limit: 0.5 mcg/mL
Toxic: > 35.0 mcg/mL
Detection limit: 0.5 mcg/mL
Clinical Significance
Oxcarbazepine (10, 11-dihydro-10-oxo-5H-dibenz (bf)azepine-5-carboxamide, Trileptal), a 10-keto analogue of carbamazepine, is an anticonvulsant for the treatment of both generalized tonic-clonic and partial seizures in children and adults. It can be administered alone or as adjunct to other anticonvulsants. Clinically significant effects of oxcarbazepine are observed when plasma levels of its active metabolite, 10-OH-carbazepine, are between 15 and 35 ug/mL. Toxic symptoms may occur when plasma levels exceed 35 ug/mL. The therapeutic mornitoring of oxcarbazepine and its active metabolite are important for achieving proper serum/plasma concentration to inhibit epileptic seizures and avoid adverse effects. The precise mechanism of the action by which oxcarbazepine and its active metabolite exert their antiseisure effect is unknown. However, in vitro electrophysiological studies indicate that they produce blockade of voltage-sensitive sodium channels, resulting in the stabilization of hyperexcited neural membranes, inhibition of repetitive neuronal firing, and diminution of propagation of synaptic impulses. These are important in prevention of seizure spread in the brain. In addition, the increased potassium conduction and calcium channel activities may contribute to the antiseizure treatment effects. After oral administration, oxcarbazepine is readily absorbed in the body, followed by rapid and almost complete metabolization to 10-OH-carbazepine, active metabolite. The half-life of oxcarbazepine is only 1 to 2.5 hours, while that of 10-OH-carbazepine is 11 to 15 hours. The protein binding of oxcarbazepine is about 67%, whereas that of the metabolite is about 38%. The clearance of oxcarbazepine and its active metabolite from the body is mainly through ketone reduction and O-site conjugation with glucuronic acid rather than oxidative processes via cytochrome P450 system. More than 95% of the treatment dosage is excreted by the kidneys. Fecal excretion accounts f
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153
Last Updated: January 29, 2020
