Interesting article that could possibly (?) underline the fact why TSH isnt the best measure of thyroid function

[Justiina]

I cant understand all scientific jibberjabber jargon, but reading this article and references , i get the idea that thyroglobulin can overcome TSH which would explain why TSH only is a poor marker of thyroid function. Correct me If i am wrong!

hindawi.com/journals/aen/20...

[helvella Administrator]

It certainly suggests that thyroglobulin is a very powerful influence - but leaves it a bit open how the whole story runs. Thank you.

Good to remember that even TSH isn't all the same! There are different glycosylation states for it - but testing just measures "TSH". No-one really seems to care about this - but I am convinced it is important in some way.

If you really want to stir things up, have a read through some of these papers about thyrostimulin. (Please don't assume I have read them all! Just managed to get started on a couple and am having a mental storm trying to take in all the consequences. )

ncbi.nlm.nih.gov/pubmed/?te...

[Justiina in reply to helvella]

Thanks for the link, looks interesting indeed.

Yeah, more research is needed, but was interesting that TG has that type of role. But it shows how complex thyroid function can be it's not fully know or understood and still it's called easy to fix!

[Justiina in reply to helvella]

Been reading that stuff a bit and indeed it's interesting! In the end there are several factors affecting TSH levels making it very unreliable to measure the wellbeing of one.

From somewhere else I read that it's mistakenly considered the golden standard because it's one of those things you can measure that accurately so it has lead to false idea of it being good marker of thyroid status.

And as we know it tells how hypothalamus pituitary axis is functioning. If one's brain is satisfied with less T3 their TSH would never rise very high as the demand of brain tissue was achieved with less effort leaving the rest of the body very deficient?

And if in some cases high TSH causes swelling of pituitary wouldn't that compromise the function of pituitary same way than tumour and could result in similar situation than in secondary where other hormones could be compromised too? So that would partially explain low cortisol which would then bounce back when TSH is lowered as swelling of pituitary would reduce as well.

Lots of ifs and buts!

[helvella Administrator in reply to Justiina]

Certainly the technology that allowed us to measure TSH as accurately as we now can is pretty amazing. Yes - ability to measure something seems to grant it the role of being a good indicator - even if it is anything but.

The fact that we are still having to ask whether macro-TSH (TSH plus an antibody to TSH) has been checked when we see discordant high TSH results throws in a big question mark. As does the variability for uncertain reasons between the various assay techniques.