Just to check....blood test due tomorrow morning! - Thyroid UK

Thyroid UK

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Just to check....blood test due tomorrow morning!

WobblyX profile image
4 Replies

I’m currently on T3 5mcg @ 7am & 5mcg @ 4pm

Also Levo 50mcg & 75mcg alternate days

Doing good so don’t want my dose changed!

So I usually don’t take the Levo until after my blood test but what about the T3?

They will be expecting to see some T3 in my blood - as it’s shorter life span should I take it or not??

Advice much appreciated!

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WobblyX profile image
WobblyX
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SeasideSusie profile image
SeasideSusieRemembering

WobblyX

When taking T3, we take our last portion of our daily dose 8-12 hours before the blood test, so ideally you will take it nearer bedtime tonight depending on the time of your test, so if your test is 9am you should take your last T3 between 9pm and 1am tonight.

If you took your last dose at 4pm as normal then your FT3 result will show a false low.

WobblyX profile image
WobblyX in reply to SeasideSusie

Thanks SeasideSusie , so I’ve already taken my last done - which should have been @ 4pm but had a hectic afternoon and didn’t take it until 6pm-ish.Do you think I should just leave it at that or take another small done later tonight?

SeasideSusie profile image
SeasideSusieRemembering in reply to WobblyX

I wouldn't be taking more than my normal daily dose. It's your choice but I would just leave things as they are and accept that you are going to have a false low FT3.

T3 has a half life of 24 hours, so there will still be some FT3 measurable.

WobblyX profile image
WobblyX in reply to SeasideSusie

Thank you!

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