Advice for protocol before bloods: Hi, I’ve read... - Thyroid UK

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Advice for protocol before bloods

SLC76
SLC76

Hi, I’ve read on here many times that you shouldn’t take your levothyroxine the morning of your thyroid blood tests (taking it straight after bloods instead) but I’m a little confused about what I should do about taking my T3.

I currently take 2 first thing in the morning, 1 at midday and 1 at 3pm - all 5mcg tablets. I read that you should leave 6 hours after taking T3 before bloods, but as I have my last tablet at 3pm and get my bloods drawn at 9am in the morning, I’m not quite sure what the best thing to do is to ensure I get the most accurate results.

I would be most grateful if someone in this lovely community could advise me.

Thank you so much. 😀

6 Replies
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SeasideSusie
SeasideSusieAdministrator

SLC76

For Levo, the time gap between last dose and blood draw should be 24 hours.

For T3, the time gap between last dose and blood draw should be 8-12 hours. This is because T3 is no longer detectable in the blood after 12 hours (although it is in the cells for 2-3 days). If you take T3 to close to blood draw then your FT3 result will show a false high. If you take T3 more than 12 hours before blood draw then your FT3 result will show a false low.

To get a proper result for the amount of normal circulating hormone, it would be best to adjust the time of your T3 the day before, taking your last dose between 9pm and midnight.

SLC76
SLC76
in reply to SeasideSusie

Thanks so much. So maybe I should take one dose of T3 in the morning, one in the afternoon, one early evening and one at midnight the day before - does that sound good to you? X

SeasideSusie
SeasideSusieAdministrator
in reply to SLC76

That sounds fine, just remember timing of T3 where food, drink and other medication and supplements are concerned. Same as Levo, one hour before or 2 hours after food, with water only and water only for one hour each side, plus 2 hours away from other medication and supplements, that's the best way to ensure proper absorption. Multi dosing is a pain :D

SLC76
SLC76
in reply to SeasideSusie

Do you think it works taking it is one entire dose? So 20mcg at once? And thank you SeasideSusie! You are always helping me out when I get stuck! X

SeasideSusie
SeasideSusieAdministrator
in reply to SLC76

It works for some people but not everyone.

I used to split my dose but got fed up of working the second dose around food, a cup of coffee, etc, so I started taking it in one dose and found no difference. I've continued taking it in one dose and take it with my Levo between 3am and 6am when I need a bathroom trip.

When I do a test, I just split the dose the day before. As I take 18.75mcg T3 then I can't halve it so I take 12.5mcg at 9am with my Levo then 6.25mcg T3 sometime between 9pm and bedtime. Then the day of the test I do my test 8.30am to 9am then take my Levo and T3 afterwards.

SLC76
SLC76
in reply to SeasideSusie

Excellent advice, thank you. I do get fed up with splitting my dose. Maybe I will give it go and take it all at once and see how I feel! Thanks for all the bloods advice - much appreciated.x

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