Summary: For patients being treated with warfarin anticoagulation, dosing of warfarin based on clinical protocols is associated with the same percentage of time with the INR in the desired therapeutic range, the same risk of an INR greater than 4, and the same likelihood of major bleeding or thromboembolism as “genotype guided” dosing of warfarin; while protocol-based dosing might be associated with lower initial costs.

Strength of Recommendation = A