T3 or FT3?

[MissFG]

I’ve had some bloods done recently at rheumatology and received a letter today.

I know my TSH is suppressed and my last bloods for FT3 we’re out of range 7.8 (3.5-6.5) but I feel good on my dose of 62.5mcg

My letter states “your thyroid function test which showed your TSH level was significantly low >0.02 and your T3 level is significantly high at 23.4”

I can’t understand why my T3 could change so much within a few weeks of blood tests.

He was a registrar so could he have misunderstood my results. Could he be telling me my T3 not FT3 result? I just can’t find the range for T3 on the nhs anywhere. Do they even measure T3?

I’m worried as he’s sent the letter to my GP and stated I should reduce thyroxine. I told him I was on T3 only, so this matter is going to confuse my GP too as they think I’m under the hospital still. Yes I said this so I could still get my bloods done periodically.

Any thoughts please?

Merry Christmas Everyone! 🎄

[Marz]

Sounds more like the FT4 - and the upper range could be 22 ?

[MissFG in reply to Marz]

I’m not on Thyroxine which was very low on my last bloods at my GP. I’m on T3 only

[Marz in reply to MissFG]

How long did you leave after taking T3 - before the test ...?

[MissFG in reply to Marz]

I wasn’t expecting them to take the test so I had a coffee and blood tests at around 11am but I don’t think it would affect my FT3 that much as it hadn’t in the past when I’ve not fasted

[Marz in reply to MissFG]

What time did you take your last dose of T3 ?

[MissFG in reply to Marz]

Ah that morning! Thank you

[Marz in reply to MissFG]

So that could explain a raised T3 reading. It is advised here to leave off T3 meds for 8/12 hours before testing.

[MissFG in reply to Marz]

I usually do but at rheumatology they wouldn’t usually test my thyroid. Hence the confusion

[BB001]

Ask your GP to retest as you think this might be a false reading as you feel so well. This time don't take that days T3 dose until after the test. Don't mention that's what you've done.

[Hormone_king7]

The time between draws and taking the prescription could be involved in the variability of your T3 results. Were they done fasting before taking your prescription or after?

[Hormone_king7 in reply to Hormone_king7]

Just caught this part of the discussion.

I agree with delaying taking prescription until after the draw.

There may also be other issues that have not been addressed, such as how well you absorb T3, blockage of absorption by dummy T3 molecules, and conversion efficiency from T4 to T3.

[MissFG in reply to Hormone_king7]

No it’s because I wasn’t expecting him to test my thyroid so had my T3 as normal thanks

[BB001]

If you are on T3 only, this may be of interest...

thyroidpatients.ca/2019/08/...

[kiefer]

This is more about convincing a doctor not to worry about his liability than anything else. Your lab result is showing the "peak" level, which drops rapidly over the next few hours. So long as there are no symptoms of overmedication, this is not a problem if the peak goes over the normal range.

The argument is that since this drug has a shorter duration of action, it should be dosed multiple times a day so as to reduce the peak levels, although I've read that some people have no problems taking their entire T3 dose once a day. This probably has something to do with peripheral thyroid receptor resistance but it won't impress any mainstream doctor. The TSH level is what makes them put their boots on in the morning.

Your only recourse is to explain that the test displayed a peak in your Free T3 blood level and that if they would like a "trough" (bottom level), then you would be happy to be retested with an interval of 8 or more hours from dose-to-blood test.

From personal experience, when I convince a doctor that I've got his liability covered, he is much more likely to trust me and go with MY plan. Offer to monitor your vital signs (BP, HR, temp) and provide it as a document to him. On that sheet add "Feeling good. No symptoms of overstimulation were experienced". That strategy worked for me.

[MissFG in reply to kiefer]

I simply explained to my GP he was a registrar and had little knowledge on thyroid and I’d taken my T3 that morning. He also stated in his letter to reduce my thyroxine which I’m obviously not on which confirmed his lack of knowledge