Cytochrome P450 3A4 Genotype, Varies
Use
This test aids in determining therapeutic strategies for drugs metabolized by cytochrome P450 3A4, like quetiapine. It helps predict drug response by identifying genetic variations that affect CYP3A4 activity, which metabolizes over 50% of drugs. Variants like CYP3A4*22 reduce expression and activity, impacting drug metabolism. However, it is not useful for drugs metabolized minimally by CYP3A4. Its interpretation assists in understanding pharmacogenomic interactions and potential dose adjustments.
Special Instructions
For cord blood samples, maternal cell contamination testing may be performed at an additional charge. This test is part of a single gene assay but also included in broader pharmacogenomics panels. It may not detect all variants affecting drug metabolism, and rare variants could give false results. Consent is needed for New York clients, and specific forms must be completed if not ordering electronically.
Limitations
This test doesn't detect all CYP3A4 activity-altering variants. False results may occur due to rare variants or if samples contain donor DNA. It doesn't predict CYP3A4 phenotype where methods differ. Drug interactions and metabolite inhibition affecting CYP3A4 must be considered. Non-detected variants don't exclude altered metabolism risk. The test doesn't determine cis/trans-variant arrangement.
New York Approved
Methodology
PCR-based (PCR)
Biomarkers
LOINC Codes
- 74007-6
- 81139-8
- 81145-5
- 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 whole blood specimen in original tube without aliquoting.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | 4 days |
| Frozen | 4 days |