If I take my last T3 dosage at 6pm is that too late for a blood test following morning at 9am?

Should I be leaving a few hours longer? Would 2 pm the previous day be better?

[Schenks]

My endocrinologist, who has phases of being a pain the the whatsit but so far has been good, says not to take any thyroid meds the morning of the test, and wants to know what time I took the evening dose of T3 (in the form of NDT - natural dessicated thyroid) because she wants to know how I am utilising it, how fast it's being cleared and so on.

So, if you have a switched-on endo they should take the time of the last dose of T3 into consideration when interpreting the results. If not, or it's it's a GP, don't take any in the 24 hours beforehand to give your body a chance to clear it and show a 'base line' result.

[Heloise]

It depends on how true you want the reading to be in my opinion. I've been trying to find out myself. It seems that T3 will peak about four hours after taking, so you don't want it to be skewed too high by taking it then but if you want to see how much remains AFTER a full dose perhaps you would want to wait. I'd be surprised if your doctor knows either but if he can tell you how T3 degrades, may he can explain the results.

I've actually done both and I'm still not sure of the true value.