Timing of dose before testing

[wellness1]

Please bear with me. I should know this by now.

I am on combination therapy and take my entire dose of Levo upon waking, along with half my liothyronine. I take the second dose midday. I was adjusting the timing as needed to conform with the advice given here, i.e., Levo 24 hours prior to blood draw and T3 8-10 hours prior. The doctor who is prescribing the T3 insists I take my last dose 4 hours prior to testing. If I am having the blood drawn at 8am, I take the Levo at 8 am the previous day. There are two scenarios for timing the T3.

1. Day before testing, take first dose of T3 at 8 am along with the Levo. Take second dose midday, as usual. Next morning take that day's first dose at 4 am for 8 am phlebotomy. Take Levo after blood draw and second dose midday.

2. Day before testing, take Levo at 8 am. Take first dose of T3 midday and take that day's second dose of T3 at 4 am the next day.

As I type this, I think it's become clear to me, but I'll throw it out there just to see if there's anything I'm missing. TIA

[greygoose]

The last dose of levo should be 24 hours before the blood draw. That bit is correct.

But, you should leave 8 to 12 hours between the last dose of T3 and the blood draw. If you take it at 4 am for a blood draw at 8 am, that will only be 4 hours, which will give you a false very high FT3 result.

[wellness1 in reply to greygoose]

Thanks for replying, greygoose. Yes, I do know that. That's how I've done it in the past. However, this endo insists on doing it this way to measure the peak serum value.

[greygoose in reply to wellness1]

Ohhhhhhh that sounds like a trap to me! Be very wary! He's probably out to reduce your dose. They can be sneaky little so-and-sos.

[fuchsia-pink in reply to greygoose]

I thought it sounded like a trap too! I'd be very wary ...

[SlowDragon Administrator in reply to fuchsia-pink]

Just say that you took T3 four hours before....but actually take as recommended.....8-12 hours before

[SeasideSusie Remembering in reply to wellness1]

I agree, I think it's a trap too.

I'd stick to what is advised here, take your second dose between 8pm and midnight the night before the test, tell your endo that you took it at 4am. Self preservation!