T3 dose before test 8hrs v 12 hrs

[Sybilla14]

What is the difference in the ft3 reading in a sample taken 8 hrs after a liothyronine dose compared to a sample 12 hrs after a dose?

I'm trying to compare two test results. Thank you.

[SeasideSusie Remembering]

Sybilla

I don't think there's much difference at all. Any time between 8 and 12 hours is recommended. Just make sure it's not less than 8 hours and not more than 12 hours.

[Sybilla14 in reply to SeasideSusie]

Thank you very much. That's very helpful. I reduced my levo dose by 12mcg in an attempt to reduce my ft3 (you did help on my previous post🙂) . Previous time I had 8h gap, this time it was 12h. My ft3 was a little bit lower (7.9 v 8.4 previously) though my ft4 went up slightly (20.6 v 19.5 previously).

I'm now starting to reduce by another 12.5mcg for a few days and increase that reduction to 25mcg for 6 weeks then retest. Does that sound sensible to you?

[SeasideSusie Remembering in reply to Sybilla14]

A total reduction of 25mcg T3 is roughly the equivalent of 100mcg Levo. That seems rather a lot, are you sure you need to reduce by that amount?

[Sybilla14 in reply to SeasideSusie]

Sorry I wasn't clear. I'm reducing Levo. I only take c20mcg of liothyronine.

[SeasideSusie Remembering in reply to Sybilla14]

Sorry, my mistake, you did say and I misunderstood. Yes, retest 6 weeks after your last dose change and see how things are then.