Thyroid UK
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Help with blood results interpretation as don't know what's going on

Help with blood results interpretation as don't know what's going on and what NDT dose to go on now. My initial post 5 days ago is here outlining my predicament then.

Blood Test results

FT3: 2.81 pg/ml (2.5 to 3.9)

FT4: 4.66 pg/ml (6.1 to 11.2)

TSH 1.487 mUI/I

I had titrated too quickly up to 3.5 grains then I took 3 days off, then 2 days on 1 grain then a day off before the blood Test, what does this mean, I was not in fact that overdosed? And I should get back on a grain schedule?

How many grains should I take now??

The blood test also showed my oestradiol was very high for a man which gets affected by my HRT so is likely the cause of my discomfort that I wrongly appropriated to the thyroid.


13 Replies


Changing dose and stopping and starting NDT will have skewed your thyroid results but you weren't biochemically overmedicated with those results because TSH isn't low and FT4 and FT3 are low.

How long were you taking 3.5 grains?

Did you stop taking it and reduce dose because you felt overmedicated?


Thanks for the reply Clutter. Yes, that's what I was thinking. I was taking 3.5 grains for about a week and a half previously.

Yes I stopped because I thought something was up, I have been anxious and not been able to calm down, really do anything at all, and I felt I was overheating and veins were always dilated, I definitely have been off, but it is hard to assign what is due to what as I am being treated with testosterone which means estrogen can balloon causing similar symptoms.

But think I misread this, as I am also being treated for Testosterone which requires estrogen to be regulated, and my estrogen was outside the range in my latest test, so very high and that is likely why I misconstrued feeling over medicated. I think that is the reason why I have felt poor the last 2 months.

I may have been over medicated, but not severely so, as I have felt ok the last few days, not too cold or anything. It has been complicated, but I intend to have regular blood tests, every 3 weeks to try and get this under control. I have made a mistake and titrated up too quickly with the grains.

I am not sure what dose to go on, now. I could try 2 grains (1 when I wake up and 1 at 3pm) for the next 3 weeks. And then see what the retest says.But that could be under dosed, as I did dose up at 2 grains as I was still very cold. But i may not have given it enough time.



What dose Levothyroxine were you taking prior to taking NDT?


I have never taken Levothyroxine.

I am thinking 2.5 grains, but this may be under-dosed. I would hazard a guess at somewhere in the 2-3.5 grains range—seeing as a couple of days off from 3.5 grains made me outside the ranges in FT3 and FT4



Okay, if you'd not been taking Levothyroxine then 3.5 grains was a very high dose to start. Thyroid replacement should be introduced and built up slowly and gradually. Can you remember what your thyroid levels were before you started taking NDT?


I did build up, but quite fast, and most probably too quickly, over the space of 1.5-2 months or so.

Before NDT my results were TSH 5.33, FT4 10 (12 -22), FT3 3.4 (3.1-6.8)



Try 2.5 grains for 6 weeks and have a thyroid function test after 6 weeks to check levels. Leave 8-12 hours between last dose and blood draw.


Ok thanks Clutter! I am going to have a blood test in 3 weeks, to check on some other hormones (I have had enough of wasting months of life at a time, and realise the cost saving is not worth it, you can't treat hormonal problems by guesswork), it is not much extra cost to include the thyroid hormones as I am in France and now realise it is absurdly cheaper. So I was thinking of getting them done as well.

Will it provide some insight if I am on the right track, or is it too early? I know T4 builds up over more than 3 weeks, and the body has to accommodate to the new dose.



I'd wait. 3 weeks isn't long enough.


OK, I'll include it in the next round of tests, hopefully after the test in 6 weeks I will have sorted out my other hormonal levels and can get tests increasinly spaced apart.


Hey Clutter,

I did get them done as it was basically no extra cost/hassle, I feel like they show I'm on the right track, or can you really not tell?

I am not going to change my dose as it is early days and definitely feel more normal, thanks for your help Clutter. I had a few queries that you may be able to answer and if you have any thoughts on the results than please say. All the best


Hey clutter,

as you were so helpful last time, I made a new post:

I forgot this advice with my new test, the leaving 8-12 hours, I basically didnt take anything the day before or on the day of the test which was at 7am. So my last big dose would have been 2 days before, as I take 2 grains am, 1 grain pm.

And would appreciate if you have any thoughts on whether I should go up. I did decide to change to 3 grains pretty early on, so it has been 6 weeks or so with 3 grains.


Right I did measure the thyroid panel as it was a very small amount to get them done as an add on to a blood test for a different issue

So I have been on 2.5 grains since my last test, and have felt ok, perhaps a bit colder than people my age but difficult to say if there is anything specific to the thyroid.

I’m definitely in the right ball park now, I think 2.5-3 grains seems right. I have felt so much better already , from sorting out another hormone issue, it is certainly life changing! It robbed 3.5 years of my prime years , but I am just thankful that I can live life now, and hopefully be unencumbered, that is amazing. health is the cornerstone of everything.

My Latest results

FT4 (6.10-14.45): 9.13 pmol/l (from 6.01)

FT3: (3.95 to 6.16): 4.99 pmol/L (from 4.44)

TSH: 0.152 (from 1.49)

So I am planning to just continue with 2.5 grains even though it may be underdosed as I am at the low end of the ranges and then having a repeat test in 3 weeks before deciding if I need to go to 3 grains. My TSH is quite suppressed, but not completely. I am currently taking 1.5 at 5-6am and 1 at 3pm.

Is this a sound strategy?

I did not take my NDT for 24 hours before the test, does this give a false low reading?

Does anybody know anything about lab ranges, for the FT3 and FT4 I am abroad and the stated ranges seem a lot lower than in the UK even though the units are the same. Say for FT4 the range is 6 - 14 pmol/L but in the UK it is like 12-20?? (And I'm hoping my results have this calibration discrepancy as well)

I assume this is nothing to worry about, but don’t really understand why.


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