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Cytochrome P450 2D6 (CYP2D6) 14 Variants and Gene Duplication
0051232
Ordering Recommendation

• 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.

Mnemonic
CYP 2D6
Methodology
Polymerase Chain Reaction/Fluorescence Monitoring
Performed
Varies
Reported
7-14 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
 
Collect
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). 
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
Plasma or serum. Specimens collected in sodium heparin or lithium heparin. 
Remarks
 
Stability
Ambient: 72 hours; Refrigerated: 2 weeks; Frozen: 1 month 
Reference Interval
By report
Interpretive Data
Background Information for Cytochrome P450 2D6 (CYP2D6) 14 Variants and Gene Duplication:
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.

Compliance Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test. However, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing. Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Note
CPT Code(s)
81226
Components
Component Test Code*Component Chart NameLOINC
2001304CYP2D6 Specimen31208-2
2008925CYP2D6 Genotype
2008926CYP2D6 Phenotype
* 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.
Aliases
  • 2D6
  • Antiestrogen metabolism
  • CYP
  • CYP2D6
  • CYP2D6 drug metabolism
  • Cytochrome
  • Cytochrome P450 2D6 Genotype for Tamoxifen Hormonal Therapy, Saliva
  • P450
  • P450 Genotyping
  • Tamoxifin Drug Metabolism