Immunoassays used by most laboratories are inaccurate for thyroid hormones, particularly at the low end of the reference interval.

[Timsywhimsy]

I just came across this study and knew you’d all be interested. Easy to understand and well worth the read. I’m going to call my lab tomorrow and see if they can perform this new type of test!

ncbi.nlm.nih.gov/pmc/articl...

[Lora7again]

Well I definitely know mine is inaccurate because there has been a time when my TSH was 0.80 and my T4 and T3 were in range but low and I felt hypothyroid and was virtually bedridden. Now my TSH is 0.37 and feel well and I am not on any thyroxine.

[Timsywhimsy in reply to Lora7again]

Are you on t3 only?

[MissGrace]

I was really hoping this would refer to TSH too - that is, a low reading could be inaccurate. It would help so many people on here who all know a low TSH does not mean you are feeling dandy or that your medication can be reduced. 🤸🏿‍♀️🥛

[Treepie]

This may be why GPs rely on TSH .I am often told FT4 and FT3 are too variable.

[diogenes Remembering in reply to Treepie]

GP's have got this mixed up. The assays are generally precise enough in that each of them gives close to the same result on the same serum at different times. It's their accuracy which is most questionable - that is do they give the right answer (are they constructed to determine the actual value well enough.

[Treepie in reply to diogenes]

That does beg the question as to why we insist on the necessity of having the tests if the accuracy is suspect?

Pleased you are still involved in the research.We met at the Birmingham Conference and you told me your wife is from the village where I live.

Snowing here and no doubt where you are.

[helvella Administrator Thyroid UK]

diogenes has already replied to previous posts of this link.

Using liquid chromatography-tandem mass spectrometry (LC-MSMS) in laboratories is, I believe, unfeasible.

[Timsywhimsy in reply to helvella]

Is it just too expensive? It may not be necessary once someone had convinced gp to prescribe t3 and you’re no longer bottom of range, but a test like this could be very useful for someone with a rigid doctor.

[helvella Administrator Thyroid UK in reply to Timsywhimsy]

Have a read here:

healthunlocked.com/thyroidu...

[Timsywhimsy]

Thank you Helvella, though I must admit I’m confused. By all of it! I don’t understand this doctors motivation for promoting a bad test.....

But again thanks, I hadn’t seen the post. The healthunlocked search engine isn’t great, to say the least

[helvella Administrator Thyroid UK in reply to Timsywhimsy]

You are beyond right re the seach engine here! (Amazingly, it is better than it used to be. )

Kudos? Research funds? Some sort of patent or other interest?

Not that I have any idea, just general ideas as to why someone might do something.

[Angel_of_the_North]

And that's without even mentioning biotin or heterophilic/monoclonal antibodies

[penny]

Why do you allow her to dictate your health? I’m not advising you as I’m not a medic but dosing on tsh is a big mistake; much has been written on here about this. My tsh is almost unmeasurable but as I don’t bother with my GP, and he has said that he isn’t interested, I have no issue with my tsh.