ARUP's Laboratory Test Directory

Carbamazepine Epoxide and Total : 0092211

Mnemonic: CARB EPOXT

Methodology: Quantitative Liquid Chromatography-Tandem Mass Spectrometry/Quantitative EMIT Immunoassay
Performed: Mon, Thu
Reported: 1-5 days
Specimen Required: Patient Prep: Obtain trough specimen after steady-state is achieved (3-5 days). Draw within one hour prior to next dose. The epoxide half-life is 6-10 hours.

Collect: Plain red. Also acceptable: Lavender (EDTA), pink (K2EDTA or K3EDTA), or green (sodium or lithium heparin). Also acceptable (avoid if possible): Serum separator tube or plasma separator tube (follow preparation instructions below).

Specimen Preparation: Separate serum or plasma from cells within 2 hours of collection. Transfer 2 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 mL)
SST or PST: Serum or plasma in a gel separator tube stored at room temperature is acceptable if separated from the gel within 6 hours. Serum or plasma in a gel separator tube stored refrigerated is acceptable if separated from the gel within 2 hours.

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Citrated plasma. Tubes that contain liquid anticoagulant.

Stability (collection to initiation of testing): After separation from cells: Ambient: 48 hours; Refrigerated: 6 days; Frozen: 1 month
Reference Interval:
 
Components Therapeutic Range
Carbamazepine-10, 11 Epoxide Not well established
Total Carbamazepine Therapeutic Range: 4.0-12.0 µg/mL
Toxic Range: Greater than 20.0 µg/mL

Interpretive Data: The 10, 11 epoxide metabolite has anticonvulsant activity similar to the parent drug.  The expected range following chronic therapeutic dose (5.2-20.0 mg/kg) of carbamazepine is 0.5-2.0 µg/mL. 
CPT Code(s): 80156; Carbamazepine, total; 80299 Carbamazepine, Epoxide
Cross References: 11 Epoxide (Carbamazepine Epoxide and Total), Atretol (Carbamazepine Epoxide and Total), Biston (Carbamazepine Epoxide and Total), Calepsin (Carbamazepine Epoxide and Total), Carbamazepine and Epoxide Metabolite (Carbamazepine Epoxide and Total), Carbamazepine-10 (Carbamazepine Epoxide and Total), Epimaz (Carbamazepine Epoxide and Total), Epitol (Carbamazepine Epoxide and Total), Epitrol (Carbamazepine Epoxide and Total), Equetro (Carbamazepine Epoxide and Total), Finlepsin (Carbamazepine Epoxide and Total), Sirtal (Carbamazepine Epoxide and Total), Tegretol, Metabolite (Carbamazepine Epoxide and Total), Telesmin (Carbamazepine Epoxide and Total)
 
 

 

 

 
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