Thought I'd check my Warfarin level. Used my Coaguchek machine (I am experienced as I've been using it for 2 years) I have had one of those silly days ,it took me 3 error messages -all my own fault - and I only got it right on the 4th time. So I'm sitting here with 4 bloody fingers and broke as I've wasted 4 test strips. To add insult to definite injury I'm out of range at 1.8 !!!