What is the appropriate amount of time to wait between taking t3 and having blood drawn to get an accurate result?

[puncturedbicycle]

Even when I have no hyper symptoms my results are sometimes out of range (hyper/high t3) even after 9 hours. I'm on 75mcg t4 and 25 t3.

[Moggie]

I usd to stop mine for two days (not that I am suggesting you do this of course) and my TSH still used to come back 0.02. I suppose it depends how low your results are and where you want to get the to.

Moggie x

[puncturedbicycle in reply to Moggie]

Apologies - when I say hyper I'm referring to high t3 results. Have edited question.

I should also say that the tsh is of little concern - it's the high t3 that causes issues for me and my doc. x

[shaws Administrator]

I take my dose around 7 a.m. and next day I have an early blood test and take T3 afterwards, so I leave about 24 hours between. If you take yours at night I would miss this dose and take next morning.

By 'hyper' do you mean you have a very low TSH. If so, that's normal for someone on T3 alone low TSH and high T3. This is from Dr Lowe:-

For someone taking 100 mcg of T3, we expect your pattern of lab results—a low TSH and high T3. However, your TSH and T3 levels are irrelevant to whether you're overstimulated or not. Two studies we just completed confirm other researchers findings: these tests are not reliable gauges of a patient's metabolic status. Many patients taking T3 have TSH and T3 levels like yours but still have severely low metabolic rates. Their metabolic rates become normal only when they increase their dosages further. Their metabolic rates become normal and they have no detectable overstimulation.

web.archive.org/web/2010103...

I mentioned to my GP the other day that the thyroid gland hormone blood tests are tied in with levothyroxine, not T3 alone and may not correlate.

[puncturedbicycle in reply to shaws]

Apologies - when I say hyper I'm referring to high t3 results. Have edited question.

I'm trying to find a dose of t3 which makes me feel good and not overmedicated. Doc is v flexible so not a worry, but my health is the concern.

I understand the argument that the test lacks credence because of the immediate release of t3 so I also pay attention to symptoms/BB test. It would be good if I could use bloods as a guideline, so I'm trying to figure out how best to do that.

Your method makes sense. Last time I had bloods I had a private test and an nhs test (long story) within 36 hrs of each other. There was a 24 hr gap (between meds and test) for the first test and that night I took a tiny dose of t3 just to keep me upright. Took the second bloods the next day approx 9 hrs after meds and came out hyper.

[mumcat2]

I was very interested to read the replies posted. Since I returned to T3 a couple of weeks ago I've become convinced that I can feel the doses wearing off. I really dread having to go off it for 24 hours because it's made such a difference to me both physically and mentally. Will you post how you get on with the abstention?!

[puncturedbicycle in reply to mumcat2]

Hiya. Well I can already tell you because the tests I'm asking about were done in Dec. I had a private test and an nhs test within 36 hours of each other. For the first test there was a gap of 20/21 hrs between my last dose and the test. This test showed t3 within range. By that evening I was just very tired really so I took a small dose - maybe 12.5? - half what I usually take, about 9 hrs before the test. I think I missed the second night's dose of t4 as well. This test showed t3 over the range (hyper).

If you can, I would suggest having the test on a day when you don't have much to do before the test, because I do feel quite sleepy without my t3. I'm lucky I guess(?) because I'm also on t4 which kind of kept me going I guess.

[Aurealis]

This is all a very interesting discussion, thanks for asking the question - I've had T3 over the top of the range when I've taken morning dose before having test (if feeling poorly, I'm not well enough to drive to have test done without taking T3 first). When I'm well I take morning T3 after having an early morning test and these are usually in range despite taking a small dose of T3 at 5pm previous day - I've been told that the half life for T3 is 3 hours, so after 6 hours 3/4 of it has gone, and after 9 hours there 1/8 th of original dose remaining etc ( hope I got the maths right there!) Bizarrely this means that when my dose is too low overall and I'm poorly, my test results come out higher (because I take T3 before test), madness. I'm taking T4 at bedtime also.