Thyroid UK
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Thyroid Function Tests

TSH <0.02 mlU/L 0.27 - 4.2

FT4 22.0 pmol/L 12.0 - 22.0

FT3 4.9 pmol/L 3.1 - 6.8

Diagnosed about 25 years ago currently taking 100 mmg thyroxine having dropped down from 125 mmg. GP sent me to Endo as increased heart rate 86 as convinced overdosing. Endo says same and suggests I cut down even more but hypo symptoms increasing!

Any comments gratefully received. Have been on greater amounts of thyroxine but no noticeable improvement.

8 Replies


Those results/symptoms could possibly show that you are still over medicated.

Although your FT3 is not overly high.

Did you take your meds on the morning of the test?

For future reference, you would get a better response to this sort of thing in the Question section.




Thanks Louise. No meds on day of test. Dr S has upped my meds in the past up to 200 which didn't seem to make any difference. This is the first time I've had all three readings. Endo only suggested TSH on lab form so lab must have looked at other readings. Have always functioned best with unmeasurable TSH. Just wondered if not utilising T4. Since these readings am looking at temperature as used that for years and was very reliable but now that's all over the place-adrenals?


Hi I agree with Louise but may be it would help to be o less T4 and a little, say 20mcg of T3..Your FT3 is low but most GP`s will not prescribe it if tSH is low. Armour etc may be better but GP`s usually will not prescribe, so you have to buy it, less expensive than T3, all on private scripts. Never take beta Blockers before a test either, make a vast difference.

Best wishes,



I have thought the same Jackie. I have just been searching for my letter from the Endo. I thought I was initially told my FT3 reading was 4.7 not 4.9. I didn't get any ranges given either. I had a follow up appointment with Prof W and asked for the ranges. He didn't want to tell me , can't remember the reason now but I asked again saying a number didn't mean anything to me so was told it was 'normal' but there was someone observing so I stuck to my guns and he told me the top end only! So again meaningless. For all I knew the bottom could have been 0.1 lower than my reading. I have since asked at the surgery for my lab report and was told they had only had a letter to rang Prof's secretary who wouldn't send them without asking as he doesn't like sending without an understanding of what they mean. He rang me and said he would send but all I got was a fabricated letter about results taken a month earlier than bloods! I spoke to practise manager who has got them for me and waived the charge this time and that's where the 4.9 came from. At the same time I had these bloods done I also when to see a private GP paid for a FT3 as I'd been turned down by the Endo. That came back at 4.6, same references. As I was planning a hectic holiday I was struggling to see how to cope so I got some Nutri Thyroid and dropped some of the Levo. I feel much better but not finding to easy to dose. Sleeping better overall. Though still tend to wake between 3 and 4 but juggling until I see Dr S again but just wondered if anyone else has any suggestions. I was put on Beta blockers for a year-BP dropped like a stone, 104/60 but heart rate no difference so private doc took me off them so again none before bloods but may have been weaning myself off. Only had a small dose of 5, forgotten units, in the first place. Could they have masked results by only stopping on the day?


When your FT4 is that high, it seems you are not converting enough of that T4 to FT3 and possibly have a high reverse T3. If you want to know for a certainty you would have to test both FT3 and reverse T3 at the same time.

This shows other reasons:


Thank you Heloise for such a detailed and complex reply. I shall certainly look into this and try to get more tests done. Trying to get my GP on board is likely to be a sticking point though I am prepared to get tests done privately. Finding someone to interpret results will probably be the problem. However this is a good starting point. I have noticed over the last few years that increasing T4-possibly to help the adrenals, makes very little difference to my wellbeing but getting FT3 tested is so difficult. This is the first time it's ever been done! I asked the Endo if I could have it tested and was told it was a waste of time as it does nothing! When the results came back I had a TSH value which was the only thyroid value he requested-I noted what was requested on the lab form so I got FT3 tested privately around the same time. When I then asked why had I got FT 3 result when he said he wouldn't do one. There was a quick shuffle of papers and he said he'd never said that! He didn't want to tell me the range and when I repeated the request he would only tell me the upper limit. I had to ask the practise manager at the surgery to get the full profile. It was then that I got the FT3 figure which seems higher than the first figure I was given and a FT4 reading that he had neglected to tell me about. I suspect that the lab realised something was wrong and extended the initial request. I need to get to the bottom of this and quickly so thank you for your valued contribution.


silverfox, I hope you pursue this. At this juncture, thyroid patients must not be kept in the dark and transparency regarding the treatments available should be acknowledged. Your metabolism really dictates your life and in some cases....survival. It is crushing to read what some of your citizens are going through. Hold your ground.


Thank you! I won't let this drop


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