NDT and timing of blood tests

Hi All,

I have been reading the following article and it has left me with questions about the best way to time my blood tests.

tiredthyroid.com/blog/2015/...

I am currently just starting self medicating on NDT (Thiroyd) and have arrived at a dose of one grain taken at 8am. I expect I will need to increase this over time and would like to get some guidance from blood tests. The article has made clear to me that FT3 fluctuates a great deal and the FT3 result will depend on the time the blood is taken, more than the actual amount of NDT taken. Given this, I am wondering how I should time the blood draw in order to get a useful result? I don't care much about the TSH result, not having a doctor to placate. As for the FT4 result, as T4 has a longer half life I wonder if it makes much difference if I take or don't take the NDT on the day of the blood draw.

In summary, my choices seem to be:

1.

Don't take the NDT on the day of the blood draw. Results will then be baseline for FT3 and FT4 no matter what time of day the blood draw is done.

2.

Take the NDT as usual on the day of the blood draw. Do the blood draw 6-8 hours afterwards. Results will show my operating levels of FT4 and FT3 at the trough for the FT3 supplied by the NDT.

3.

Take the NDT as usual on the day of the blood draw. Do the blood draw 3-5 hours afterwards. Results will show my operating level of FT4 and FT3 at the peak for the FT3 supplied by the NDT.

So which way do you think would be most helpful as I step up the NDT and why? Opinions gratefully received.

June

2 Replies

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  • I leave 24 hours after ndt, early morning blood test before food.

    The t3 in ndt peaks after a few hours.

    I had a surprise blood test one day and had already taken ndt a few hours earlier.

    My t3 was 12.1 and the hospital freaked out at me.

    It was taken again the next day , no ndt this time and it was 5.1.

    So i would recommend your first option.

  • Shonnyuk,

    Many thanks for your most helpful reply. How interesting that your t3 varied by so much.

    I can't see a reason why the hospital would blame you for your elevated t3 result if they didn't notify you in advance that they would be doing a blood test. That is blaming you for their ignorance and incompetence. I hope it didn't upset you too much.

    Taking your info into consideration I think I am going to go with option 2 for the moment. I am choosing this because my t3 and t4 results should be higher than for option 1 but not so high as to be unhelpful. This should give me earlier warning that I am getting close to my correct dose of NDT and need to be careful. Maybe after I have got there I'll try option 1.

    June

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