Hi
I've seen my gp recently who I had a really bad appointment with I have posted it on here but when I also mentioned about TSH not being the best indication of one's thiyroid health wouldn't T3 be a better indication he said that T3 only has a short life so theirfore its not recommend for thyroid health then he went on about TSH being the best test.... Is this true does T3 only have a half life... Lost.... 🤔
T3 has a short half-life of about 24 hours but is secreted throughout the day as well as being made from deiodinased T4. T3 are relatively stable throughout the day provided the patient is not taking any T3 medication and doesn't have an out of control thyroid. TSH is subject to variations during the day and menstrual period. In terms of assay results fT3 will give more stable results than TSH. TSH can be a very good indicator of thyroid stauts but this is not always so.
See Fig 1 in academic.oup.com/jcem/artic... .
Thank you, u asked, a great question, I needed this☄
Not only does T3 have a half-life of 24 hours in the blood, but what gets into the cells stays there for about three days. Doctors just use this 'short life' business as an excuse not to prescribe or test T3. It's all bunkum.
Hi greygoose ❤️
Thought that might be the case just keep us I'll then😠😠😠
So is it more expensive to test fT3 then? If it all costs the same, I'm not sure why you wouldn't do T3 as the go-to test rather than it being the last choice ...
As far as I know, and FT3 test costs the same as an FT4. It's just penny-pinching on the part of the NHS. And, another reason not to test it is because doctors don't understand the results, they know nothing about T3. Why do they know nothing about T3? Because that's the way Big Pharma likes it - and BP controls what is learnt in med school - we might get better if doctors knew more about T3, and that would cost BP money!
Hi fuchsia-pink
According to my GP who I had a really bad appointment with rammed down my throat that TSH is the best test to see how our bodies are responding..he wouldn't listen to me when I mentioned T3 being the active hormone. He rambled on about the T3 only having a short life in the blood then when on to bombard me with some gobldygook about not testing T3,T4 as their is no point as they change throughout the day.I also asked him if this was the best test for me as I have no thiyroid I must say he became very irritated prob A,he had no idear what he was saying B,he was pushed for time,C he is restricted by NHS guide lines..no matter what his first priority should be his pacients welfare and how they are feeling expense should not come in to it I now always ask for T3 and T4 the last blood work he did he did not do these tests I went back and asked another GP to do them she did no problem 👍🏻 and also a small foot note when I was rushed in to hospital in thyriod Storm my sister in law told me the A&E requested immediate T3,T4 and TSH so if T3 and T4 are not good indicators why did A&E need them....🤔🤔🤔
TSH is a very good first test, it will tell you if your thyroid is malfunctioning and in which direction (is it overactive or underactive?). It's a bit like if your car will not run you first check if you have gas/petrol in the tank or if your television isn't working first check, is it plugged in? After establishing that you will need more accurate and diagnostic testing and for that you go to T4, T3, FT4 and FT3 plus antibodies.
My recommendation is that you do not argue with your doc about which tests because that is like spitting down a well. Just get all the tests you are curious about (like your T3 and FT3 levels) via medichecks (or True Health Labs if you are in the US) then (with our help) diagnose your problem yourself and take the appropriate action. You will need a doc for prescriptions but you can fiddle the dose yourself and take supplements to maximize your T3 generation (selenium will probably do that for you).
Regarding the diurnal variability of T3 or FT3, just make sure you measure at the same time each time you get a blood test and under the same circumstances (e.g. don't party the night before SOMETIMES, ) Just do what you always or usually do, then you will have a good baseline and significant relative data. Btw, the half life of T3 is quoted between 8 hours and 24 hours so don't hang too much on that factor. However, have your blood test always at the same time because you will get a great variation if you take it in the morning one time then the afternoon the next. Best to do blood tests in the morning before taking your meds and before breakfast.
These things are pretty much what I do. My (ignorant on thyroid matters) GP sometimes makes the great decision that it is time to check my thyroid and he does a TSH and T4, I always get the blood test while I am in his hospital (we have docs in hospitals here in the US) because it is a great big waste of time especially with today's traffic to drive back another day. He tells me my TSH is suppressed and that I should reduce my dose (of NDT) I take no notice and so I remain very well.
Hi thanks for that info... ❤️❤️❤️
Lol....my intern Endo professes his love for the mighty TSH test too and everything else is no good. This type of thinking is the very reason thyroid patients remain sick.
If it all possible please get another doctor. You yourself could possess a medical degree, and get nowhere with this kind of thinking (from your Dr.) see comment from Birkie.
Unfortunately we cannot get the kind of medical attention we need without a Doctor who listens to the patient and realizes they are intelligent beings or they wouldn’t be coming to see them in the first place. Does that really have to be mentioned out loud?! Patients ARE a big part of the SOLUTION - they are in there with the disease, (Hello!).
Cease to hit your head against this brick wall of a Dr., and you will see amazing results all the more quickly. Do get back with us and let us know how it goes.
My Endo was the same. I asked him how he knows he has oil in the car. He looked shocked but said "the dipstick". So you measure the oil circulating then? Not what is in the sump or on the shelf?
I said I wanted to know how much hormone was circulating and not in my sump. He got the message...eventually.... 
My latest Endo letter and need research to dispute TSH only
Testing TSH only?! 
abnormal tsh
T3 only pregnancy 
