I posted my latest results since taking T3 yesterday but have just read on another post about stopping meds prior to being tested. Are we not supposed to miss the T3 dose? I took mine about three hours later than normal-would that have made any difference to the result?
My T3 was 5.0 (3.1 - 6.8)
Thanks a lot 
It is best to have a gap between taking thyroid hormones and the test. Taking it before a blood test will skew the results and may result in doctor adjusting your dose of hormones. If taking levothyroxine a gap of 24 hours is advised, between last dose and test and taking it afterwards.
It is the TSH the doctors only take notice of and it would be quite low if you'd taken hormones a short time before.
It's best to leave a 12 hour gap between your last dose of T3 and the blood draw. If you take it just before the test, it won't affect your TSH, because the TSH doesn't react that quickly. But it will give you a falsely high FT3. You'll only be measuring the dose you just took, not what is normally circulating in your blood.
Greygoose,
Do you know WHEN exactly you measure what is normally circulating in your blood; 12 or 24 h after taking any drugs containing T3? I am trying to figure out myself how to interpret my lab results...
I would say 12 hours. 24 hours would give you a very low FT3.
Thanks, that's what I suspected...I waited 24 h after having labs, ended up with very low FT3 levels, and then raised dose only to end up with hyper symptoms...so what you say makes a lot of sense. Thanks again
About half way between doses is a good time, it will give a good indication of your average level. I take L-T3 at breakfast and bedtime so I usually have my blood taken in the afternoon.
Hmm...I left a gap of more than 24 hours so does that mean my T3 could now be too high?
Assuming L-T3 has a half life of 24 hours you would have 50% left after 24 hours (mathematical genius). After 12 hours you would have about 70% left (the decay curve is not a straight line). So if you multiply your result by 70 and divide by 50 you will get a decent approximation of an average figure. Simpler, just multiply your fT3 result by 1.4.
Oh dear-that means my T3 is now out of range! I feel fine though-no rapid heart beat, pulse slow as normal. Not sure what to do now 
Do I take thyroid meds before blood test
Levo before blood test?
Stopping B12 before blood test? 
T3 before blood test?
Help please with meds before blood test.
