Blood result

I wondered if anyone could advise me. In was diagnosed 6 weeks ago with underactive thyroid with a tsh reading of 181. I was advised a normal reading would be 5 so this is extremely high. They medicated 75mg Euthyrox and asked me to come back in 6 weeks to be retested. My result have come back normal despite me feeling very unwell some days and weak. Could the fact that I took my medication 2 hours before bloods give an inaccurate result? Any guidance would be appreciated. 

9 Replies

  • Oh gosh yes, taking your meds before your test hasn't helped at all. You should leave 12-24 hours after taking meds before blood draw, have the earliest possible appointment in the morning, don't eat breakfast, water only, then take meds and have food after blood draw not before.

    What is your new test result? What are they classing as normal? When on thyroid meds the aim is to get TSH to 1 or below. What about your FT4 and FT3? When newly diagnosed , it normal for doctors to retest after 6-8 weeks, adjust meds, retest again after another 6-8 weeks, adjust again if necessary until bloods are in range and symptoms abated. Your TSH should be low in range as mentioned, FT4 and FT3 in the upper quarter of range.

  • Well I have been back and the GP disagrees and says no need to be retested, wait another 6 weeks. My TS4 has gone from 181 to normal reading of 3.61 within 6 weeks but I still have all the symptoms.  The thyroid scan that I had a week ago also suggests chronic thyroiditis but I have just been told to be patient as time is a healer and to be retested in 6 weeks....

  • Was FT4 and FT3 tested also the first time, or just TSH? With a TSH so out of range, especially as you didn't have a diagnosis at the time, I would expect the lab to test at least FT4 also.

    Although with your second test 3.61 is in range (presumably, as you haven't  given the range ), I can understand  the lab doing only TSH, but your GP should be more on the ball and aiming for a TSH of around 1 whilst keeping your FT4 and FT3 within range and taking your symptoms into account, tweaking meds if necessary.

    Chronic thyroiditis is Hashimoto's disease I believe (autoimmune thyroid  disease). Have your TPO and TG antibodies been tested? If antibodies are raised this confirms Hashimoto's. With Hashimoto's you can dampen down the autoimmune attacks by going gluten free, some people also need to be dairy free.

    It sounds as though  your GP doesn't know very much about thyroid disease.

  • Thank you for your response, going to ask.for a print out. How do I know if I have Hashimoto? When reading up there is very little difference in treatment. I do feel like my whole body is shutting down sometimes, I suppose something I need to get used to, this has turned my life around.

  • Hashimoto's is confirmed by raised antibodies. Testing for Thyroid Peroxidase antibodies and Thyroglobulin antibodies will confirm (or not) the presence of autoimmune thyroid disease (Hashimoto's). If the antibodies are raised that confirms Hashi's.

    It looks something like:

    Anti-Thyroidperoxidase Abs - XXX.XX <34

    Anti-Thyroglobulin Abs - YYY.YY <115

    So with TPO Abs if the number is greater than 34 Hashi's is confirmed, similarly if TPO Abs are greater than 115 then again Hashi's is confirmed. Quite often only one lot of antibodies is raised and that still confirms Hashi's. I think the NHS may only test TPO Abs, and they have to be requested, it's not normally done as standard.

    I'm not an expert on Hashi's but I don't think there is any difference in treatment. There are swings in test results and symptoms caused by when the antibodies are attacking, which is why going gluten (and some dairy) free is recommended as that should reduce the attacks.

    Definitely get a print out of your results, don't let your surgery fob you off, you are entitled to them (Data Protection Act). And when you next see your GP, ask for B12, Vit D, ferritin  and Folate tests, these all need to be optimal (not just in range) for thyroid hormone to work properly.

    A good idea is to create your own health file. Gather all your results, chart them - result plus the reference range, what medication and dose you are on, symptoms, etc. Then you can refer back to it in the future, it can help in future discussions with your GP.

  • Thank you, you have been very helpful. Not been tested for Hashimotos but I will ask to be tested. 

  • Michelle1976,

    What are your results with the ranges?  Normal is a broad range.  Most people will feel well after TSH is 1.0 or lower with FT4 in the upper range.  Symptoms can often lag a couple of months behind good biochemistry.

    Levothyroxine should be taken after your blood draw to avoid skewing the FT4 result which may peak within a couple of hours of taking Levothyroxine.


    I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

  • My doctor has disagreed that the meds may have intefered despite my ts4 reading going dramatically down from 181 to 3.6

    My thyroid scan from 4 days ago also suggests chronic thyroiditis and all i can do now is wait for my next 6 week scan....

  • Michelle1976,

    Taking Levothyroxine before a blood draw skews FT4 result (if tested)  but it won't affect TSH result.  You've responded very well to Levothyroxine for TSH to have dropped to 3.61 in only 6 weeks but 3.61  is still high for most people.  Symptoms can lag several months behind good biochemistry but you should be feeling some improvement now TSH is lower, although it may take up to a year for all symptoms to resolve.

You may also like...