Warfarin Response Genotype, Varies
Use
This test is used for assessing CYP2C9, VKORC1, CYP4F2, and rs12777823 for variants affecting the metabolism of warfarin (Coumadin). It is useful for identifying patients who may require warfarin dosing adjustments, particularly those being started on warfarin, who required multiple dosing adjustments to maintain INR in the therapeutic range, or who have a history of thrombosis or bleeding when taking warfarin.
Special Instructions
Genomic DNA is extracted from whole blood or saliva. Informed consent for genetic testing is required. After DNA extraction, multiple genotype tests can be performed on a single specimen. Reflex tests include fibroblast culture, amniotic fluid culture/genetic test, STR-based comp analysis, and maternal cell contamination studies in cord blood specimens with maternal sample at additional charge.
Limitations
Due to lower quantity/quality of DNA from saliva, some aspects may not perform as well as from whole blood; gene regions not interrogated will be noted and additional specimen may be required. Samples from patients with recent transfusions or transplants may include donor DNA and may not accurately reflect the recipient’s genotype; pre-transplant DNA specimen recommended. Method may not detect all variants, absence of detectable variant does not rule out altered metabolism; cis/trans status of multiple variants may be unknown.
New York Approved
Methodology
PCR-based (PCR)
Biomarkers
LOINC Codes
- 93196-4
- 46724-1
- 50722-8
- 54451-0
- 93197-2
- 93198-0
Result Turnaround Time
3-10 days
Related Documents
For more information, please review the documents below
Specimen
Extracted DNA
Volume
at least 100 mcL at 75 ng/mcL concentration (preferred)
Minimum Volume
Not provided
Container
Screw Cap Micro Tube, 2 mL with skirted conical base; acceptable: Matrix tube, 1 mL
Collection Instructions
Include concentration and volume on tube; DNA must be extracted in a CLIA-certified laboratory using validated extraction platforms.