6 STUDY TESTS 6.1 INR and Fiix-INR Current patients on stable warfarin therapy (see 5.4.1) can be included. In new patients, no later than after the first dose of warfarin should the dosing be managed by the AMC staff at Landspitali. The VKA dosage will be adjusted to maintain the Fiix-INR or the INR (PT-INR) with the therapeutic target of 2.5 (range 2.0-3.0).