Urgent phone call Free T4 is now 4, what does this mean?


I've had my thyroid function tests done for my diabetes review and just received an urgent phone call to my mobile from Health Care Direct 111 service. My Free T4 is 4 and I need to phone my GP tomorrow.

I explained to the Dr. that I was on Liothyronine for nearly 2 months now since my endocrinologist took me off Armour for my treatment for underactive thyroid and thyroid cancer suppression. He wasn't sure what to do as he could not access my medical records to find out what past results were. I explained that my TSH has to be suppressed to stop the cancer returning because I still have some thyroid gland remaining.

Any ideas why this sudden change? My Free T4 is normally at the low end of the range between 11 to 14 and my Free T3 between 3 and 5.

Any ideas gratefully appreciated as I'm now panicking.

Thank you.

TT x


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14 Replies

  • Don't panic. :) You're ok, nothing's going to happen overnight, even if the results are lower than they should be.

    How much levo and liothyronine are you taking?

  • Don't worry .......When I was taking liothyronine my t4 was always very low. As you are not taking any t4 and only taking T3 your getting the active hormone directly so all you will have in your system is the small amount your thyroid is still making or some residual left over from the NDT...... I have had a few panicked phone calls over the years about low T4 or suppressed TSH. Most people are on Levo so when something different comes along they have no idea how to read and interpret the results, hence the panick......my last serum T4 level was 2.9

  • If you are taking T3 in sufficient quantities your thyroid doesn't bother producing much T4. I was on T3-only for most of 2015/ very early 2016, and when I did tests in January this year my results were :

    TSH 0.1 mu/L (0.27 - 4.2)

    Free T4 1.94 pmol/L (12 - 22)

    Free T3 4.1 pmol/L (3.1 - 6.8)

    I'm still alive. :D

    However I no longer take T3-only, I take mostly NDT with a smidgen of T3 at bedtime. I found T3-only left me feeling that something was missing, and so did NDT on its own. But the two together is working well - and my Free T4 is still well under range.

  • Thank you all for your replies

    I'm glad it's not too serious. I was on 1&3/4 grains of Armour thyroid until 7 weeks ago when endo took me off due to cost to his budget, cancer hospital refused to fund and own gp refused due to it not being licensed. I've been on 40mcg of Mercury pharma t3 since withdrawal of Armour and I feel ill again and I've returned to Zombie Mum state again with all the hypo symptoms. I've ordered a generic NDT from the USA 10 days ago so hopefully it will be here soon and I'll be back to my better self. I'll ring my gp just to check the results but I'll not waste much time on it.

    If there's anything else I should do then please don't hesitate to let me know.

    Once again, a big thank you to you all.

    TT xx.

  • That's rough for you 😕 So unfair. Hope you feel better soon.

  • Hi All,

    Thanks for your posts.

    I've seen a new GP at my surgery and he was very good and understanding. He said that there's nothing to worry about because as I'm on T3 I would not make much T4 anyway because I don't need it. He checked my TSH and it's seriously suppressed as it should be stop the thyroid cancer growing back. He said that he would be concerned if my TSH was rising whilst on the T3 but because it's not there's no need to worry. It was a relief to see a GP that knew what he was doing.

    Panic over and thanks to everyone that posted on here and put my mind at rest.


  • If you are on Liothyronine only you would expect your T4 to go down really low. So not a cause for concern.

    Did they test free T3, that is really the only useful measure, because your TSH will be suppressed by the T3

  • Hi,

    No they didn't test T3 and I think this was part of the panic. I've got a print out from my GP yesterday and notes say that I'm not on thyroid medication when I am.

  • My tests also say I'm not on thyroid meds when I am. I've only ever been tested for tsh and t4. My doctors seem to think that's all that is necessary. Should I insist on other tests and do you have the same problem. Ive been feeling really crap for a while now.

  • Hi,

    They only seem to do blood tests for TSH and Free T4 because it is believed that if your Free T4 is in range then you are converting Free T4 to Free T3 adequately even if you are not. GP's are not very clued up on Thyroid problems so you might be better asking for a referral to an endocrinologist.

    TT x

  • Are you still taking T3 or NDT? If, yes, don't worry about it if Free T3 is high in range. If you are on T3 only and taking enough of it, your thyroid (what's left of it) doesn't really need to make any T4 (if you were on NDT, FT4 would probably be higher as there is some in the NDT) Most doctors don't understand how T3 works.

  • Hi,

    I was on Armour until 7 weeks ago when my endorinologist took me off it but, I'm now on T3 and feel unwell. I much prefer the Armour.

  • If endo doesn't like Armour why not suggest T4/T3 combo?

  • Endo is fine with Armour and he has prescribed it for nearly 18 months but he is being audited and risks losing his license because he's the only endo in my locality prescribing Armour. Plus his budget cannot pay it any longer, the cancer hospital won't pay for it even though it's for my cancer treatment and GP won't prescribe due to it being unlicensed. I've had T4 monotherapy, T4/T3 combined therapy, Armour (made me feel a lot better) and now T3 only therapy because my GP will prescribe it even though I feel ill on it.

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