TSH problems in diagnosis

[diogenes]

This paper highlights the problems of using TSH in diagnosis.

Hindawi Journal of yroid Research

Volume 2019, Article ID 4106816, 8 pages

doi.org/10.1155/2019/4106816

Review Article Challenges in Interpreting Thyroid Stimulating Hormone Results in the Diagnosis of Thyroid Dysfunction

Salman Razvi Sindeep Bhana, 2 and Sanaa Mrabeti3

Thyrotropin (TSH), is regarded as the primary biomarker for evaluating thyroid function and is useful in guiding treatment with levothyroxine for patients with hypothyroidism. (e amplified response of TSH to slight changes in thyroid hormone levels provides a large and easily measured signal in the routine care setting. Laboratories provide reference ranges with upper and lower cutoffs for TSH to define normal thyroid function. (e upper limit of the range, used to diagnose subclinical (mild) hypothyroidism, is itself a matter for debate, with authoritative guidelines recommending treatment to within the lower half of the range. Concomitant diseases, medications, supplements, age, gender, ethnicity, iodine status, time of day, time of year, autoantibodies, heterophilic antibodies, smoking, and other factors influence the level of TSH, or the performance of current TSH assays. (e long-term prognostic implications of small deviations of TSH from the reference range are unclear. Correction of TSH to within the reference range does not always bring thyroid and other biomarkers into range and will not always resolve the patient’s symptoms. Overt hypothyroidism requires intervention with levothyroxine. It remains important that physicians managing a patient with symptoms suggestive of thyroid disease consider all of the patient’s relevant disease, lifestyle, and other factors before intervening on the basis of a marginally raised TSH level alone. Finally, these limitations of TSH testing mitigate against screening the population for the undoubtedly substantial prevalence of undiagnosed thyroid disease, until appropriately designed randomised trials have quantified the benefits and harms from this approach.

[1tuppence]

Thank you, diogenes.

[TorcHouse]

Thanks for this, and it will be useful ammunition.

I love the bit at the end, about not initiating mass screening. Like the PSA blood test for male prostate problems, it could still be a flag for further watching, or even - shock-horror - testing the full thyroid panel.

[diogenes Remembering]

One of the ironies I find here is that TSH as a diagnostic aid is queried in this instance, yet once treatment is started on T4, it suddenly converts to being indispensable in controlling thyroid disease. This isn't logical: problems in one situation don't extrapolate to perfection in another. This attitude is cherrypicking. And the reason is as always: emerging hypothyroidism cannot be described as a medical fault, but treatment falls under guidelines or"forced-lines" where a false sense of certainty comes about by anxiety of litigation and thus defensive praise of TSH as a perfect diagnostic test in therapy. This for me is why TSH is being tenaciously held onto; it is a shieldwall against what is seen as illegitimate complaint.

[Noelnoel in reply to diogenes]

“Finally, these limitations of TSH testing mitigate against screening the population for the undoubtedly substantial prevalence of undiagnosed thyroid disease”

So to simplify/clarify: Is this paragraph saying that large numbers of us are walking around undiagnosed but that TSH testing isn’t a reliable diagnostic tool

[shaws Administrator]

Diogenes - the GP who phoned to inform me that I had no problems at all and that was when the TSH was 100, so I am sure that few actually have know what a TSH indicates and they are unaware of how they should respond if TSH is too low or too high.

[tattybogle]

Thanks for posting this... i first read it when i was still a lurker on here and was just starting to realise the emporer had no clothes on.

It's nice to re-read it now though ~ understanding it is much easier than it was the first time round .

( and it was my first introduction to the existence of human-anti-mouse-antibodies .. which still make me laugh)