Thyroid Function tests still vary between manufacturers

[diogenes]

I've sent this paper to Lyn at TUK as it's behind a paywall. It shows how little progress has been made on harmonising test results between manufacturers' products. You would think that if numerical tests are to be used, the medical profession would insist on equivalent results wherever obtained from which product. Think again. They bandy about results but don't bother where they come from. 10 years of toil and little to show for it!

THYROID Volume 33, Number 9, 2023

ª American Thyroid Association DOI: 10.1089/thy.2023.016

Thyroid Stimulating Hormone and Thyroid Hormones (Triiodothyronine and Thyroxine): An American Thyroid Association-Commissioned Review of Current Clinical and Laboratory Status

Katleen Van Uytfanghe, Joel Ehrenkranz, David Halsall, Kelly Hoff, Tze Ping Loh, Carole A. Spencer, and Josef Kohrle

[Loafinabout]

Spitting nails here! I’ve have only come across one GP in my life who took the trouble to get to grips with the Thyroid function. Consultations with her were collaborative and dosage ‘arrived at’ when I felt well and could live a normal life. Since then I dread medication reviews as every other doctor I’ve had has been blatantly ignorant and, however diplomatically I tried, didn’t have their ‘listening ears on’🙄

[Wua13262348]

Don't know if I am off topic here or not, but are you aware of any thyroid blood testing company in the UK who use an Abbott machine, where you are able to take biotin supplementation as part of a B complex, as normal, without stopping it before a test?

I have a reason for wanting to test whilst taking biotin, but not if it skews the thyroid test like it does with the Roche machines, where biotin is used as part of the testing process.

I read on the internet that Abbott machine-testing would make this possible. Medichecks and Blue Horizon don't use Abbott.

[diogenes Remembering in reply to Wua13262348]

The Abbott FT4 test is a two-step method and I don't think biotin affects it. However, ithe FT4 test is very poor, has a range very different from others, and doesn't obey the classical tests of valid assays.

[Wua13262348 in reply to diogenes]

Many thanks for your input. Waste of time then trying to track one down. A question I think , very much suited to your expertise.

[diogenes Remembering in reply to Wua13262348]

Unhappily, there is strong evidence that the purchase of tests and the use of them is under two apparently noncommunicating people: the financial hospital purchaser and the doctor who diagnoses from the tests bought. That is, in short, the users are indifferent to the quality of the tests they use and the finance department buys the cheapest, without any knowledge of what they are actually getting. Nearly all FT4 and FT3 tests by the popular producers fail to obey a basic tenet, that when diluting the serum, the FT4 or FT3 test result should hardly change. This is a physical chemistry point, and I shan't expand on it here. BUT there is a test group that I and colleagues produced which does obey the rule. Yet it figures little in the literature, because of the more powerful muscle of the big sellers eg Abbott. The meeting between doctors' knowledge of what they are using and quality of test source to get a diagnosis is totally lacking, and it is a scandal that this situation has come about.