Another blood test but already taking thyroxine?

Another blood test  but already taking thyroxine?

Hi all

I have been trying to get a trial of thyroxine after 2 early miscarriages and a TSH at 3.40 and tpoab of 339.

GP has refused treatment but a private endocrinologist has given me a trial of thyroxine - 25mg for 3 months.

I decided to get a blue horizon test done last week before I start any treatment, results attached.

I posted these Blue Horizon results to my GP. GP called me today saying that they would need to do their own blood test. I said okay on the phone but when I got off the call I remembered that I've been taking thyroxine for the last 2 days and have increased my vitamins supplements.

I can't get an appointment with my GP before my blood test which is booked for next Tues.

What should I do about the thyroxine affecting my test results?


12 Replies

  • Two days of 25 mcg levothyroxine will make little difference to the blood test results, just stop taking it until after the blood is taken. In any event given your results 25 mcg is likely to be too little and if you are planning pregnancy you should receive more careful monitoring. The high antibody counts mean it is likely your thyroid hormone levels will jump around a little so once you are pregnant they should monitor you closely.

    It's reasonable for your GP to want to do their own blood test. The Blue Horizon result for total T4 is weird, if this isn't a typo then the test is likely to be invalid.

  • Thanks. Just want it acknowledged on the NHS so that I'm pregnant they monitor it properly rather than me having to go private. Annoying to stop taking thyroxine and I feel like a pin cushion but hopefully it will be worth it

  • Whether they know about you being hypo or not, unless you find an ally you may have to advocate very strongly for yourself and your health. They really don't take a lot of notice of thyroid problems. Unless in a fertility context they are more careful in which case forgive me, I am just bitter, lol.

  • Jimh111, there was insufficient blood to test TT4.

  • And insufficient brain cells to notice the '1' was an 'I' and insufficient didn't mean low. Thanks.

  • Stop taking the thyroxine until after your blood test next week. The fact that you've taken 25mcg for two days probably won't make any real difference, it's such a small amount that it probably won't have had any effect yet.

    On the day of your test, make the appointment as early as possible in the morning, 8.30-9.00am, and fast (you can have water). This should give you as high a TSH as possible which is what you want. Eat breakfast after your test.

  • Thanks, the appointment is 730 am. Should I eat very little the night before as well?

  • Have your evening meal as normal then nothing until after blood draw.

  • MollieMoo, did you not manage to fill the blood container? I'm wondering if the TT4 result is saying insufficient because there wasn't enough blood to complete every test.

  • Hi I had the same result of tt4 from BH too. They said it means they didn't have enough blood to test for that. I emailed them and they sent me another kit to do the tt4 again free of charge.

  • Yes the Tt4 was because there was not enough blood but blue horizon said that TT4 is thought to be of less clinically relevance than FT4 so wasn't sure whether to go ahead.

  • TT4 is not much use, it is only relevant in some rare conditions and some research studies.

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