Split NDT and blood test- what time do I take the last dose?

[AnnaSo]

Hi everyone,

I have a blood test tomorrow, I didn’t plan for it and not sure what’s the best approach here to get an accurate read. I had half a grain 8am, 1 grain at 2pm and I am due for another half a grain today still. What time do I take it? The test will be at 8:30am.

Thank you! ❤️

[waveylines]

I wouldn't take any more today so you have 24hrs clear.

[AnnaSo in reply to waveylines]

Hey waveylines, isn’t 24h for Levo? From what I remember NDT and T3 only are 8-12 but I am not sure what are the rules for split doses.

[waveylines in reply to AnnaSo]

Think your forgetting that ndt has t4 in it which requires a 24hr gap. Whilst the T3 will run down quicker, the bulk of a ndt is actually the t4 componant. If it were me Id stick to a 24hr gap. Thats what my endo told me.

[Paula101]

I would also leave a 24 hr gap due to the T4 as wavelines has also said 🙂

[AnnaSo in reply to Paula101]

Hey Paula! I side with Susie’s thinking and that what I’ve read before, wanted to check if it’s the same for split dose. If you leave 24h your get false T3 read. It only works for T4. Do you leave 24h? From what I remember you’re also on NDT? 🙂

[SeasideSusie Remembering]

AnnaSo

It's usually recommended on here that 24 hours is for Levo, and 12 hours for NDT and T3.

Yes, there's T4 in NDT, but T4 has a long half life - about 7 days - so that's not going to change much. T3 has a much shorter half life and when on NDT or T3 then it's the FT3 result that is most important so that you know if you are undermedicated or overmedicated or taking the correct amount to keep your FT3 in the right place. If you leave 24 hours between last dose of NDT and blood draw you will get a false low FT3.

[AnnaSo in reply to SeasideSusie]

Thanks Susie, that’s what I thought but wanted to double check as this will be my first NDT read so don’t want to make a mistake 🙂

[Paula101]

I've learnt something new then 😊