Overview: Warfarin Sensitivity TestIntroduction: The Warfarin Sensitivity Test detects warfarin sensitivity to guide anticoagulation therapy, preventing clots. Following 2023 CPIC guidelines, it uses PCR for high specificity, supporting genetic screening. This test is critical for guiding dosing, treatment planning, and improving outcomes in molecular pathology for patients requiring anticoagulation.
Other Names: Warfarin Genotyping Assay, CYP2C9/VKORC1 Test.
FDA Status: Laboratory-developed test (LDT), meeting molecular pathology standards for diagnostic accuracy.
Historical Milestone: Warfarin sensitivity testing began in the 2000s with pharmacogenomic research. PCR methods improved in the 2010s, enhancing diagnostic precision.
Purpose: Detects warfarin sensitivity genotypes to guide anticoagulation therapy, prevents clots, and evaluates patients with clotting disorders.
Test Parameters: 1. Warfarin Sensitivity Genotype
Pretest Condition: No fasting required. Collect whole blood, buccal swab, or saliva. Report history of clotting or anticoagulation therapy.
Specimen: Whole Blood (EDTA, 2-5 mL), Buccal Swab (sterile swab, 1-2 swabs), Saliva (sterile container, 1-2 mL). Transport in a biohazard container.
Sample Stability at Room Temperature: 24 hours
Sample Stability at Refrigeration: 48 hours
Sample Stability at Frozen: Not frozen
Medical History: Document clotting events, bleeding, or history of anticoagulation therapy. Include current medications, especially warfarin.
Consent: Written consent required, detailing the tests purpose, anticoagulation implications, and risks of sample collection.
Procedural Considerations: Uses PCR to detect CYP2C9 and VKORC1 genotypes. Results are available in 3-5 days, supporting clinical decisions. Performed in laboratories, often for pharmacogenomic screening.
Factors Affecting Result Accuracy: Low DNA yield or contamination can affect results. Sample quality impacts specificity.
Clinical Significance: Warfarin sensitivity genotypes (e.g., CYP2C9
2/3, VKORC1 -1639G>A) guide dosing, preventing bleeding or clotting. Normal genotypes suggest standard dosing.
Specialist Consultation: Consult a hematologist or pharmacologist for result interpretation and dosing adjustments.
Additional Supporting Tests: INR, PT, or genetic counseling to guide anticoagulation therapy.
Test Limitations: Specific to warfarin metabolism; other anticoagulants may require different tests. Sample quality affects sensitivity.
References: CPIC Pharmacogenomics Guidelines, 2023; Clinical Pharmacology & Therapeutics, Johnson JA, 2022.
