Carbamazepine, Free and Total, Serum or Plasma
Also known as: CARB FT
Use
This test is used to optimize drug therapy and monitor patient adherence for carbamazepine. Therapeutic drug monitoring is essential, as carbamazepine is subject to drug-drug interactions due to displacement of protein binding and extensive metabolism. Cross-reactivity with metabolites may occur, and calculating percent free carbamazepine can help in dose optimization. The therapeutic monitoring is especially important for patients with altered or unpredictable protein binding capacity.
Special Instructions
Patients of Asian ancestry with the presence of the HLA-B*15:02 variant are at increased risk for Stevens-Johnson syndrome or toxic epidermal necrolysis when treated with carbamazepine. Pharmacogenetic testing for HLA-B*15:02 is recommended prior to treatment for patients at risk.
Limitations
The test may not reflect the total burden of carbamazepine in all patient populations due to variability in protein binding. Cross-reactivity with metabolites may account for differences in carbamazepine concentrations among various analytical methods used.
FDA ApprovedNew York Approved
Methodology
Immunoassay (Quantitative Enzyme Multiplied Immunoassay Technique)
Biomarkers
LOINC Codes
- 3433-0
- 32852-6
- 3432-2
Result Turnaround Time
1-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
1 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Collect serum pre-dose (trough) draw at a steady-state concentration in plain red.
Storage Instructions
Refrigerated.
Causes for Rejection
Whole Blood, Citrated Plasma, tubes containing liquid anticoagulant, or Serum separator tube (SST).
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 5 days |
| Refrigerated | 5 days |
| Frozen | 3 months |