Cytochrome P450 2B6 Genotype, Varies
Use
This test aids in determining therapeutic strategies for drugs metabolized by the CYP2B6 enzyme, including efavirenz and sertraline. It helps resolve genotype‑phenotype discordance, is useful in research and drug trials, and may identify genotypes when previous less comprehensive methods were used. Allele variations guide prediction of metabolizer phenotypes per CPIC guidelines. Poor or ultrarapid metabolizer status may warrant dosage alterations or alternate medications when dosing guidance is unclear.
Special Instructions
Testing is available as this single gene assay or within the psychotropic pharmacogenomics panel (order PSYQP). Reflex tests (e.g., for maternal cell contamination in cord blood specimens) may be performed at additional charge. Consent forms and pharmacogenomic association tables are available.
Limitations
The assay may not detect hybrid alleles (CYP2B6/CYP2B7); over 38 named alleles exist, and individuals reported as *1/*1 may still carry unknown variants. Rare variants may cause false results. Samples from recent transfusions, stem cell or liver transplant recipients may yield inaccurate genotype. The test does not provide specific dosing recommendations and should assist—not replace—clinical decision‑making.
Methodology
PCR-based (PCR)
Biomarkers
LOINC Codes
- 72511-9
- 72882-4
- 79720-9
- 104666-3
- 69047-9
- 48767-8
- 85069-3
- 62364-5
- 18771-6
Result Turnaround Time
3-8 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
Not provided
Container
Lavender top (EDTA) or yellow top (ACD)
Collection Instructions
Invert several times to mix blood; send in original tube; do not aliquot; postnatal umbilical cord blood acceptable.
Patient Preparation
A previous hematopoietic stem cell transplant or liver transplant interferes with testing.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | 4 days |
| Frozen | 4 days |