After 25 years on Thyroxine, blood results are now odd!

[JojoDee]

I was diagnosed with hypothyroidism 25 years ago and have been of thyroxine ever since. The TSH and T4 test were more or less in sync up to about a year ago. I am now getting high TSH (12.9miu/L) and my T4 is near the top of the limit at 19.4pmol/L. I was taking 150mg of thyroxine for many years but started to get heart palpitations. The doctor lowered my dose to 125 because my T4 was above the limit despite TSH being high!

I just wondered if this scenario has arisen after I was in hospital where the nurse made sure I took this medication with a full glass of water and didn't consume caffeine drinks or food for at least 30 minutes after taking them! I have strictly kept to this routine ever since. However, I still don't understand why the TSH result still suggests I am undermedicated.

Also does anyone else have a low resting pulse rate. Mine is down at 50bpm and was up at 57 when I was on 150mg of thyroxine.

I would like to know if anybody else has similar results.

[greygoose]

How many times have you had this high TSH result? What is it usually? Do you ever get the FT3 tested? Do you have Hashi's?

[JojoDee in reply to greygoose]

4 times since May 2023. Before that, it was less than 4.2 with T4 running at 20. FT3 has, not to my knowledge, been tested. I understand I have Hashimoto's.

[greygoose in reply to JojoDee]

OK, well, having Hashi's does complicate everything but I don't really see how it fits in here. I just asked to get the full facts.

I think the best thing you could do is get private testing to include FT3. For one thing, you need to see how well you're converting - I suspect you aren't converting well at all. But for another things, to see if testing in a different lab makes a difference to the TSH. Could happen. If you know you have Hashi's, you just need a basic test without antibodies, just TSH, FT3 and FT4. Be interesting to see the results.

[tattybogle]

I have similar, but my TSH is nowhere near as high as 12.

I had high end fT4 / very low TSH for many years , but now find myself with TSH just over range, and fT4 still right at the top.

in my case , i think the most likely reason is that my fT3 is now much lower than it used to be. previously 40-60% through range .... now only 13%

( i assume this is because my conversion of T4 to T3 has worsened for some reason full result here healthunlocked.com/thyroidu... )

but your TSH 12 seems too high for that explanation to fit .

definitely worth looking at what your fT3 is doing though.

is this first TSH result that is weirdly high ?, or has it been rising over a few tests ?