Thoughts on this paper?

[strawberrysorbet]

I've been reading through various medical papers and came across this one. I wondered what your thoughts were on this and the suggestion that euthyroid patients with elevated FT results are caused by "interference" and don't give the true FT reading for the individual?

clinchem.org/content/54/7/1...

[helvella Administrator Thyroid UK]

My thoughts? If you take FT3, FT4 and TSH together and they are all in accord with each other, this is probably not an issue. If, however, the tests are discordant or (as is so often the case) only one or two tests are performed, there is every reason to look further and consider interference.

I have several times posted about macro-TSH - which is formed when anti-TSH antibodies attach to TSH - which can make TSH look very elevated when it isn't.

[strawberrysorbet in reply to helvella]

Thanks Helvella.

Can the same apply in the case of euthyroid patients with low FT4 or FT3? Could it be simply due to interference?

[diogenes Remembering]

Interference from natural antibodies in blood (uncommon) that happen to bind T4 or/and T3, on FT4 and FT3 assays has been known for 34 years. I really don't know why researchers keep on publishing results whose artefacts have been known about for ages. A ridiculous high result in either test immediately indicates the presence of such antibodies and a simple detection method can soon identify their presence. These antibodies often occur for a short time in the blood of patients on T4 - they come and go in quite short time periods. For clinicians this isn't a problem because it's obvious when it occurs.

[Treepie]

Researchers need to publish to get recognised to climb the greasy pole.