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At a Glance
Why Get Tested?
To determine whether you have CYP2C9 and/or VKORC1 genetic variations and are likely to need lower, or less commonly, higher than average doses of the "blood-thinning" drug (anticoagulant) warfarin
When to Get Tested?
A health practitioner might order this test prior to prescribing warfarin for you; a health practitioner may sometimes order it when you are being treated with warfarin and have had bleeding or clotting episodes or dosing difficulties
A blood sample drawn from a vein in your arm
Test Preparation Needed?