New results - made a BIG mistake!: Would love... - Thyroid UK

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New results - made a BIG mistake!

Would love some input on my latest results please!

I made a BIG mistake and took my 100mg of Levo 3 hours before my blood test- i just totally forgot not to take it! I did tell the nurse but they said to do it anyway.

So results as follows;

TSH 1.48 (0.27-4.20)

FT4 28.4 (9-26)

FT3 4.36 (3.1-6.8)

Previous results on 75mg were as follows:

TSH 1.61 (0.27-4.20)

FT4 18.2 (9-26)

FT3 2.9 (3.1-6.8)

How much of a difference will it have made to my FT4, taking my Levo so close to the test?

My TSH and FT3 don’t look to me like i’m overmedicated.

Thanks for all comments / help 😀

13 Replies

Given that you're a very poor converter, and comparing the two sets of results, it's possible that it hasn't made much difference at all. But, possibly 20% difference - so the result if you hadn't taken your levo could have been about 25. But, it's impossible to say with any accuracy. However, that nurse is a bit of a lunk-head, telling you go do it anyway. You now have no real idea what your FT4 level is. Still, one consolation, they're not likely to ask you to reduce your dose with that TSH. :)

1 like

My endo has said he’s ‘very happy to try me on T3’ - given the new results below, so you think it warrants trying it?


Yes, I think it does.


Ah okay, so I thought it would make more of a difference than that!

So if my FT4 is genuinely at the top end / slightly over range, how come my TSH isn’t lower? It that because my FT3 isn’t high?


Impossible to know exactly how much difference it made. Depends how much of your dose had been absorbed into the blood. Everyone absorbs at their own rate, and as that rate is never measured - probably can't be measured - we don't know.

TSH is not an exact science. Far too many variables. But, your FT3 being low would be a factor, yes.


You probably need to retest vitamin levels too

When getting bloods tested in future make sure to move levothyroxine away (eg into handbag) so that you don’t take Levo before blood test again


Thanks SlowDragon - I only had all my vitamins done 4 weeks ago, so thought i’d save myself a bit of money this time and just got with the FT4, FT3 and TSH.

Vitamins last time were:

Ferritin 83.8 (13-150)

Vitamin D 82.2 (50-175)

Active B12 178 (37.5-188)

Folate 19.8 (>3.89)

What do you think about the elevated FT4? Should I drop my dose back down or with my TSH still at 1.48 (0.27-4.2) and my FT3 at 2.9 (3.1-6.8) would you stay at the current 100mg dose?

Thanks for your help 😀


Stay at current dose low converters feel better with T4 above the range as well as your TSH is high


Thank you.

I wasn’t sure what was best- with my previous results my endo has said he was ‘very happy to try T3’ if increasing the Levo to 100mg didn’t achieve what we wanted it to (ie get my FT3 to increase from below range)


My Endo started me on 100mcg T4 in Jan as he had a hissy fit I was using NT and my TSH was 0.001 test 3 months later bloods done and was told to reduce T4 to 75mcg another 3months and TSH had improved slightly 1month on bloods again no real difference so he had now reduced T4 to 25 mcg with 5 mcg twice a day it’s now 2weeks and 10 more to go before bloods


I would stay on 100mcg and see if FT3 does creep least until you see endocrinologist again

If FT3 doesn't improve it's likely you will need addition of small doses of T3

How long have you been on 100mcg? It can take several months for levels to stabilise

Guidelines on Levothyroxine dose is 1.6mcg per kilo of your weight

Guidelines on dose by weight

NHS guidelines on Levothyroxine including that most patients eventually need somewhere between 100mcg and 200mcg Levothyroxine.

Vitamins look pretty good. Vitamin D may be better slightly higher around 100nmol.


Sorry, another question- why is my TSH still quite reasonable when my FT4 is so high? Is that just because my FT3 isn’t high too?


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