Time between ndt and blood test.

[Meavis]

Hello

Do I have to wait 24 hours or 12 to test thyroid levels on ndt?

Years ago my ft3 did not move and I stopped. But I did test after 24 hours was it out of my body? Is that why I did not see a difference. My ft3 is at 25% wich is 2 low.

So if I use it early in the morning do I have to take it the day before testing in the late afternoon. Because if I want to test early in the morning taking it it in the late afternoon the day before gives me like 12 hours.

Or will I get a false result because I use it only 1 day in the late afternoon and normally in the morning. How to test 12 hour if I take it all in the morning?

Nobody talks about the best time to test for ndt. Wich is strange because we will all get a different result with 2, 5,24 hours??

[fibrolinda]

8-12 hours for anything with t3 in it so yes 12hours max for NDT. I take mine at midnight normally so just take that dose earlier, 9pm, the night before blood test.

If you look at the related posts, top right, you'll see it's been talked about a fair bit 🙂

Linda x

[Meavis in reply to fibrolinda]

So if i take i normaly in the morning but for the bloodtest just in the evening for the 12 hours it will give a correct result. The test does not show result of the week before like tsh or ft4. Do you know what I mean. Don t know how to explain it.

[fibrolinda in reply to Meavis]

The time gap is so the test shows whats in your system rather than the t3 dose you've just taken. Longer than 12 hours would give a false low result for ft3. As it takes 6-8 weeks for the t4 you take to convert it's different, hence the advisory 24 hours for Levo. Oh gosh I'm confusing myself now so sorry.

The advice I was given and have followed is to leave 8-12 hour gap after t3 or NDT before blood test in order to get consistent comparable results for dose monitoring or adjustment. There are those who disagree but I trust the admin who gave me this advise.

Linda x