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Epic Code LAB484 Oxcarbazepine Metabolite, Serum

Additional Codes

Mayo Code: OMHC

Interface Order Alias: 10756

Cerner code: 8789

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Monitoring serum concentration during oxcarbazepine therapy

 

Assessing compliance

 

Assessing potential toxicity

Specimen Type

Serum Red


Specimen Required


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. Centrifuge and aliquot serum into plastic vial within 2 hours of collection.


Laboratory Test Directory Note:

COLLECTION NOTE: Volumes listed are in serum or plasma, draw approximately 2 1/2 times the requested volume in whole blood.

Specimen Minimum Volume

0.5 mL

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)

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 28 days
  Ambient  28 days
  Frozen  28 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

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.

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 (MHDC), 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.

Method Name

High-Turbulence Liquid Chromatography Mass Spectrometry (HTLC-MS/MS)

Report Available

1 to 3 days

Reporting Name

Oxcarbazepine Metabolite (MHC), S

Reference Values

Oxcarbazepine metabolite: 10-35 mcg/mL

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.

Method Description

The serum sample is diluted in acetonitrile containing internal standard. The protein precipitate is centrifuged, and a portion of the supernatant is diluted with mobile phase for detection by a tandem mass spectrophotometer (MS/MS).(Unpublished Mayo method)

Day(s) Performed

Monday through Saturday

Clinical Reference

1. Hiemke C, Bergemann N, Clement HW, et al: Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology: Update 2017. Pharmacopsychiatry. 2018 Jan;51(1-02):9-62

2. Perucca E: Clinical pharmacology and therapeutic use of the new antiepileptic drugs. Fundam Clin Pharmacol. 2001 Dec;15(6):405-417

3. Lloyd P, Flesch G, Dieterle W: Clinical pharmacology and pharmacokinetics of oxcarbazepine. Epilepsia. 1994;35(Suppl 3):S10-S13

4. Gonzalez-Esquivel DF, Ortega-Gavilan M, Alcantara-Lopez G, Jung-Cook H: Plasma level monitoring of oxcarbazepine in epileptic patients. Arch Med Res. 2000 Mar-Apr;31(2):202-205

5. Johannessen SI, Tomson T: Pharmacokinetic variability of newer antiepileptic drugs: when is monitoring needed? Clin Pharmacokinet. 2006;45(11):1061-1075

6. Patsalos PN, Berry DJ, Bourgeois BFD, et al: Antiepileptic drugs-best practice guidelines for therapeutic drug monitoring: a position paper by the subcommission on therapeutic drug monitoring, ILAE Commission on Therapeutic Strategies. Epilepsia. 2008 Jul;49(7):1239-1276

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

80183

LOINC Code Information

Test ID Test Order Name Order LOINC Value
OMHC Oxcarbazepine Metabolite (MHC), S 31019-3

 

Result ID Test Result Name Result LOINC Value
81030 Oxcarbazepine Metabolite (MHC), S 31019-3