Carbamazepine Epoxide and Total

Abbrev Code:CARBAP   
Order Code:LAB1153Order Name:Carbamazepine Epoxide and Total
Synonyms:Tegretol; 10, 11 Epoxide; Epoxide; Carbatrol; Epitol
Methodology:Quantitative liquid chromatography/Tandem mass spectrometry
CPT Codes: 80156 x1, 80156 x1, 80161 x1, 80161 x1
Test Includes:Carbamazepine and carbamazepine10,11 epoxide metabolite
Turnaround Time:Specimens are sent to the reference laboratory Sun-Sat; testing is performed on Mon and results are reported within 1-8 days.

This test uses a manufacturer labeled Analyte Specific Reagent (ASR) as the reagent providing the specificity of the assay. The test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Collection Instructions

Optimal Volume:2 mL
Minimum\Peds Volume:1.2 mL
Container:Red (no gel)
Alternate Containers: Purple (EDTA)
Collection Instructions:Usual sampling time is immediately prior to next dose (trough).
Causes for Rejection:Whole blood. Gel separator tubes, light blue (citrate) or yellow (SPS or ACD solution).

Processing and Shipping

Specimen Processing:Separate serum or plasma from cells within 2 hours of collection. Centrifuge and aliquot 1 mL, 0.5 mL minimum. Store in freezer.
Shipping Instructions:Ship on dry ice.
Stability:After separation from cells: 48 hours at room temperature; 1 week refrigerated; 1 month frozen.
Test Performed at or Referral Lab Lab Sendouts  (ARUP)
Referral Lab number:0092211


Critical Range:Carbamazepine 10,11 Epoxide:  Toxic range is >15 ug/mL
Carbamazepine:  Toxic range is >15.0 ug/mL
Reference Range:Carbamazepine 10,11 Epoxide: Epoxide not well established
Carbamazepine: 4.0-12.0 ug/mL
Therapeutic Range:The therapeutic range is based on serum pre-dose(trough) draw at steady-state concentration. The carbamazepine metabolite, Carbamazepine-10,11-Epoxide has anticonvulsant activity and a proposed therapeutic range of 0.4-4 μL/mL.
Use:A rare, adverse drug reaction to carbamazepine therapy includes Stevens-Johnson syndrome or toxic epidermal necrolysis. Patients of Asian ancestry with the presence of the HLA-B*15:02 have an increased risk for this carbamazepine-induced, life-threatening reaction. Pharmacogenetic testing for HLA-B*15:02 is recommended prior to treatment for patients at risk of carbamazepine hypersensitivity. This information has been included in the FDA approved label for carbamazepine ( and in the guidelines from the Clinical Pharmacogenetics Implementation Consortium (

A combination of therapeutic drug monitoring with HLA-B*15:02 pharmacogenetics genotyping may benefit patients at increased risk of developing carbamazepine induced adverse events due to rare genotypes other than the HLA-B*15:02 variant allele.

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