Re: over testing can lead to "chasing" the desired INR # and constantly altering dosage prematurely. I do have a morning routine that I stick with, it is possible I missed a dose, but unlikely. I did get Covid late July, and that is when INR went sub 2.0, and led to a couple days of Lovenox. Even before Covid, my system changed to how it responded to the warfarin, sometimes acting hypersensitive, and then at times almost "resistant". I have dealt with changes in metabolism in the past, and this is not like that. This is not me chasing the INR on my own, the coag clinic has overseen it all (just more guessing). Yes, I self test. I a live on an island, and it is a full day to travel to neighboring island to nearest lab. I recently checked my machine against theirs, and a blood draw, and my machine was fine. Until I get this figured out, I was wondering what a hematologist can offer?