how do they work out warfarin for the inr levels

Hello

Well I am taking Warfarin and its being up and down over the months, what \i would like to know is how they work out the medication. My INR has been creeping up once again and it was 4 yesterday so the surgery said take 4mg and go back on Tuesday to have yet another test.

I am getting nearer to St Thoms appt next week and I cannot wait as things down here are somwhat lacking.. I have a brilliant GP, Heptologist, Rheumatologist but for some reason the Haem cannot get together. Don't get me wrong, they are lovely staff but I don't feel confident with them, and forever repeating myself over and over again.

Look forward to hearing from you.

11 Replies

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  • Hi Daisy

    Which day are you up to St Thomas? The answer is I am not sure. For us Hughies I think it is a case of trial and error, as we are not generally stable enough. Each person will need a different dose to hit their target. The nurses do have a computer to help them I think, but that is about it. It is certainly not an exact science!! Have you thought about self testing? It has been brill for me, but I still use the nurses for my doseage.

    Take care. Ann

  • hI - YES THE NURSES HAVE THEIR COMPUTER ETC TO SAY WHAT DOSE, BUT THEN SOME OCASSIONS, THE CONSULTANTS EITHER SAY A LOWER DOSE OR HIGH DOSE FOR SAME INR. ALSO LAST WEEK THE INR AT DOCTORS WAS 2.0 AND THEN THE HOSPITAL DID ONE SAME DAY AND IT SAID 2.4. I AM GOING UP ON WED, STAYING OVER TILL THURS.

    I DID ASK THE CONSULTANT ABOUT SELF TESTING AND HE DID NOT SAY ANYTHING ELSE ABOUT IT. DO THEY COST ALOT?

  • Hi you will be in much more control, if you can afford a coaguchek machine, to self test. £299.00 mine cost. I hope you get the help and advice at St Thomas's when you go. You will be best writing it down how you feel. Good luck.

  • please becareful self testing, the strips used contain phosphoipid and we have antiphospholipid, I will never go to a clinic that uses the finger stick again. my inr was a whole number off when ran on a finger stick plus a venus draw. the finger stick said 3.0 while the venus draw was 2.0 and the venus draw is the most accurate way to test. Renae

  • Please read the package insert that the companies provide with their coagucheck machines. There is a warning specific to Antiphospholipid Antibody patients that the regent used on their test strips is not accurate for those with LA

    Limitations of Procedure

    The CoaguChek Systems Test uses only fresh, capillary or venous whole

    blood. Plasma or serum cannot be used.

    Use only plastic syringes without anticoagulants or additives. Glass tubes

    or syringes must not be used.

    The blood drop must be a minimum of 10 µL in volume. Low sample

    volume will cause a SAMPLE ERROR - REMOVE STRIP warning.

    This test measures PT results in persons on warfarin-type (Coumadin®)

    therapy. This test should not be used to monitor persons on heparin

    therapy. In vitro studies showed the CoaguChek Systems Tests are

    sensitive to levels of heparin over 0.15 U/mL.

    When a patient is on intravenous infusion therapy, do not collect sample

    from arm receiving infusion line.

    Hematocrit ranges between 32-52% do not significantly affect test

    results.

    No interference was found in lipemic samples containing up to 500

    mg/dL of triglycerides. Testing performed with in vitro-spiked samples

    indicated bilirubin up to 20 mg/dL and hemolysis up to 500 mg/dL did

    not significantly affect test results.

    The presence of anti-phospholipid antibodies (APAs) such as Lupus

    antibodies (LA) can potentially lead to prolonged clotting times, i.e.,

    elevated INR values. A comparison to an APA-insensitive laboratory

    method is recommended if the presence of APAs is known or suspected.5

  • Hello Daisy

    I self test with a Coaguchek xs. I have found that I am more in control, have far less running around for tests and if I "feel" my INR is wrong I can do a quick test, call my nurse and get the on going dose changed by her computer.

    I get the test strips on prescription.

    I am at St T on Thursday for my yearly visit.

    Take care

    Garry

  • Hi Daisy

    I am the same as Garry. It works well for me, and my team are all happy.

    What time are you going back on Thursday? There is a London Support group meeting, or I could come up and meet you.

  • Garry I am at St T's on Thursday as well

  • Trial and error they have a rough guide but it depends on the person, everyone is different,some people are very sensitive to warfarin while others are not and need very high doses. i personally am not usually at a stable inr level for long due to my other medications,infections etc. So regular checks and stick with it!

    Best wishes

  • Yes trial and error, as I just posted on another treat they can use a computer program but it does not work for everyone. Normally they will calculate a dose based on the range your doctor wants then test you in a few days to see how you react, and take it from there, some people need 15 mg or more daily others need 5 mg, it all depends.

    Based on my experience eavesdropping on the INR clinic for 16 years the old people don't need as much warfarin as the youngsters do.

    Usually the starting range will be 2-3, give this time to have a therapeutic effect, if you still have symptoms they will suggest a higher range.

  • I am not sure but been an intresting thread. and as hughes has said waferin can effect diffrent for youngsters to old so it depends.

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