t3 timing before blood test.

[Mothebear]

I have understood staging Levothyroxine before blood tests and stopping all biotin intake the week before, and early morning blood test.

I am new to T3, does this need to be moderated before a blood test?

Thank you.

[SeasideSusie Remembering]

Mothebear

We always suggest that the day before the test you split T3 into 2 or 3 doses (whichever is possible) and take the last part of the dose 8-12 hours before test, ie if you test at 9am then take last part of dose between 9pm the night before and 1am. Any longer would give a false low FT3 result, too close to test gives a false high FT3 result.

[Mothebear in reply to SeasideSusie]

thank you Seaside Susie

As I take one dose at 7 am and a 2nd one at 1pm, I’ll take the 7am one at about 10pm and nothing til after my blood test.

[SeasideSusie Remembering in reply to Mothebear]

You need to take your normal daily dose the day before so take your 7am one a bit later and take your 1pm one in the evening 8-12 hours before the test. If you miss a dose you'll get a false low FT3 result .

[shaws Administrator]

I take T3 alone but on the morning of having a blood test (I get the earliest blood draw) I don't take T3 until after blood draw.

I have had no queries from GP about my results. I also feel well and have no symptoms.