Ordering Recommendation

Optimize drug therapy and monitor patient adherence.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Plain red.

Specimen Preparation

Allow specimen to clot completely at room temperature. Ensure complete clot formation has taken place prior to centrifugation. Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 mL)

Storage/Transport Temperature


Unacceptable Conditions

Separator tubes or potassium oxalate/sodium fluoride tubes. EDTA plasma.


After separation from cells: Ambient: 24 hours; Refrigerated: 7 days; Frozen: 1 month






Within 24 hours

Reference Interval

Therapeutic range: 4.0-12.0 µg/mL
Toxic: greater than 15.0 µg/mL

Interpretive Data

The therapeutic range is based on serum pre-dose (trough) draw at steady-state concentration. Carbamazepine is also subject to drug-drug interactions due to displacement of protein binding and extensive metabolism. Cross-reactivity with metabolites may account for differences in carbamazepine among analytical methods.

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 prior to treatment is recommended for patients at risk for carbamazepine hypersensitivity. This information has been included in the FDA-approved label for carbamazepine (https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&varApplNo=016608) and guideline from the Clinical Pharmacogenetics Implementation Consortium (https://www.pharmgkb.org/guidelines). [HLA-B*15:02 Genotyping, Carbamazepine Hypersensitivity, ARUP test code 2012049.] A combination of therapeutic drug monitoring with HLA-B*15:02 pharmacogenetics genotyping may benefit patients who are at increased risk for developing carbamazepine-induced adverse events due to rare genotypes other than HLA-B*15:02 variant allele.

Compliance Category



Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0090260 Carbamazepine 3432-2
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Tegretol(R)
  • Tegretol, total serum concentration
  • Total Carbamazepine
Carbamazepine, Total