The Christmas Eve Graph

INR check this morning.  It dropped.  I don’t really understand it.

I haven’t had any cranberries.  I have had very small amounts of green veg (salad actually) occasionally, but not much at all.  Yet it’s dropped to 2.1.  It needs to be kept between 2-3 and, because it’s still in range, they don’t seem worried.  The dose has not been changed.  The system, INR Star, says it doesn’t need checking again for a month but we’re actually going to check it on 4th Jan, which is the day the warfarin nurse gets back from Christmas.  I’ve not got a good feeling about that next check, as it’s a downward curve.  But we shall see, I suppose.  I think my neck is probably healed by now anyway, but it’s still not the most exciting position to be in for the next 11 days.  I have a box of Clexane syringes in the cupboard, but my bruises have only just really and truly disappeared and I’ve no desire to go back.

As a layperson, I’m also not rating INR Star.  Obviously I know nothing.  But there is clearly an unexplained drop in INR, it hasn’t changed the dose, and it suggested not checking again for another month.  That doesn’t seem like a very sensible or intelligent system to me.  Though I just found this FAQ thing – not on the INR Star site – which makes me wonder if they just haven’t customised the settings on the system for me…?  I’ll ask in January.

See, now I’m wondering if I should ask for it to be checked before 4 January.  But, well, the neck is probably healed anyway and the warfarin nurse didn’t seem at all worried that it would drop or anything, so maybe it’s just one of those things.

Diet Coke and stress, by the way, if anything – there isn’t much proof – raise INR, rather than make it drop.

Happy Christmas Eve!



  1. Sorry to read that you are concerned about your recent INR results.

    In fact the important thing is not your range, but your target INR which in your case is 2.5. INRstar will only suggest a dose change when your INR moves outside a 16% margin either side of target – 2.1 – 2.9 in yur case – because that’s what the expert formula inside INRstar suggests should be the case.

    INR estimation is not an exact science and minor fluctuations are normal, so when you return to see your nurse on 4 January (because so long as everything else is OK nothng dramatic is likly to occur before then) your INR may well have fallen a little more, enough to suggest an increased dose of warfarin.

    Hope that helps


    • CN says:

      To be honest Robert, it doesn’t really. I’ve a vertebral dissection so if I fall below 2.0 I’m in danger of another stroke. I also have to go back on Clexane injections if it drops below 2.0. So all in all, the system – in my layperson, know-absolutely-nothing view!!! – is worrying. It said to stick with the same dose and get reviewed in 28 days. A human can clearly see i’m on a unexplained downward curve and, at the very least, should be reviewed far sooner than that. Perhaps I simply don’t understand…?

      • I’ve not seen a patient with vertebral artery dissection which, as you know, is extremely rare (with a M:F ratio of 1:3 so it’s even rarer in men).

        However with any condition requiring warfarin there is no sudden cut-off point where a patient is suddenly at a far greater risk of a stroke because their INR has crossed some arbitrary threshold. In other words the graph of Risk v. INR for any condition is a smooth curve, without any sudden variations signifying a dramatically increased risk.

        As far as the four week review is concerned I can understand your feeling that an earlier review might well be necessary, especially given your fears about the 2.0 cut-off. However I can’t comment on that point specifically because I haven’t seen your previous results and review periods and I don’t know exactly how your surgery has set up the options in their copy of INRstar, which was the important point you referred to in your blog.

        Best wishes


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