High FT4: Anybody could pse advise. My thyroxine... - Thyroid UK

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High FT4

janey28
janey28

Anybody could pse advise. My thyroxine was increased to 150mg from 125mg 3 months ago because I was able to persuade gp that I would feel better. Results this week are wierd to me FT3 4.5 (3.1-6.8) which is lower, TSH 0.009 (.57-3.6) also lower, ft4 19.9 (7.9-14.0). Both TSH & ft4 ranges have lowered since last tested. I’ve felt good on higher dose and body temp, bp & pulse all good

Advice appreciated thx

13 Replies

Your FT3 has dropped because your FT4 is well over-range, and the T4 is now converting to more rT3 than T3. TSH is obviously going to be very low with such a high FT4. I'm surprised you feel better with these results.

What were your results before you increased your dose?

janey28
janey28 in reply to greygoose

Sorry what’s rt3 please - last results posted under shaw

greygoose
greygoose in reply to janey28

T4 is converted into T3, which is active, and rT3, which is inert, normally in equal quantities. But, in certain circumstances, T4 converts to more rT3 than T3, so your FT3 level drops. One of those circumstances is when you're taking too much levo and not converting very well, and the FT4 level goes over-range.

Given your last lot of results, it's very strange that an increase of 25 mcg took you over the top like that. How long a gap did you leave between the last dose of levo and the blood draw?

janey28
janey28 in reply to greygoose

Thanks it was 22 hrs

greygoose
greygoose in reply to janey28

Curiouser and curiouser. So, do you take anything with biotin in it? Like a multi-vit or a B complex?

janey28
janey28 in reply to greygoose

Nope No other meds or supplements of any kind

greygoose
greygoose in reply to janey28

Then I would suspect lab error and want the test repeated.

Did the RAI destroy your whole thyroid?

janey28
janey28 in reply to greygoose

I’ve no idea but I was only told about the graves diagnosis in June and that had been disclosed on 2008. The tpo was 1400 + then.

greygoose
greygoose in reply to janey28

TPO antibodies are not a Grave's diagnosis. TPO antibodies are Hashi's. For Grave's they should have tested TRAB or TSI. Were either of those tested?

janey28
janey28 in reply to greygoose

Again no idea it was just a note from the endo after 1st consultation in 2007

shaws
shawsAdministrator

Was your blood test at the earliest possible and fasting (you can drink water) and allow a 24 hour gap between last dose and test and take levo afterwards?

janey28
janey28 in reply to shaws

Yes to your questions - last results were -

Thyroid Test 25/4/18

Ft3 4.9 (3.8-6)

TSH 0.019 (0.34-5.6)

T4 15.0 (8-18)

I went up from 125to 150g

My TPO antibodies were 146.8 (0-9)

I’m told I have Graves I was hypo until rai 10 yrs ago

Appreciate your help

Sorry misinformed I was hyper and am now hypo

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