• Assess genetic risk of abnormal drug metabolism for drugs metabolized by CYP2D6.
• May aid in drug selection and dose planning for drugs metabolized by CYP2D6.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Plasma or serum. Specimens collected in sodium heparin or lithium heparin.
- Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month
Characteristics: The cytochrome P450 (CYP) isozyme 2D6 is involved in the metabolism of many drugs, such as antiestrogens (tamoxifen), alpha-blockers, analgesics, anticonvulsives, antidepressants, antidiabetics, antihypertensives, antipsychotics, antitussives, beta blockers, cardioactives, norepinephrine reuptake inhibitors, and stimulants. Variants of CYP2D6 will influence pharmacokinetics of CYP2D6 substrates, and may predict non-standard dose requirements.
Inheritance: Autosomal co-dominant.
Cause:CYP2D6 gene variants.
Variants Tested: (Variants are numbered according to M33388 sequence.)
Functional: *2 (2850C>T), *2A (-1584C>G; 2850C>T).
Decreased function: *9 (2613-5delAGA), *10 (100C>T), *17 (1023C>T), *29 (1659G>A) *41 (2988G>A).
Non-functional: *3 (2549delA), *4 (1846G>A), *5 (gene deletion),*6 (1707delT), *7 (2935A>C), *8 (1758G>T), *12 (124G>A), *14 (1758G>A).
Increased function: Duplicated functional alleles.
Negative: No mutations detected is predictive of *1 functional alleles.
Incidence of Poor Metabolizer Phenotype: Caucasians and Hispanics-10 percent; African Americans-2 percent; Asians-1 percent..
Clinical Sensitivity: Drug dependent.
Methodology: Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: Only the targeted CYP2D6 variants will be detected by this panel. Diagnostic errors can occur due to rare sequence variations. Risk of therapeutic failure or adverse reactions with CYP2D6 substrates may be affected by genetic and non-genetic factors that are not detected by this test. This result does not replace the need for therapeutic drug or clinical monitoring.
|Component Test Code*||Component Chart Name||LOINC|
- Antiestrogen metabolism
- CYP2D6 drug metabolism
- Cytochrome P450 2D6 Genotype for Tamoxifen Hormonal Therapy, Saliva
- P450 Genotyping
- Tamoxifin Drug Metabolism