[i][b]Evaluation of FT4 Levels by Immunoassay Requires Specific Reference Intervals in Pregnant Women[/b][/i]

[helvella]

Evaluation of FT4 Levels by Immunoassay Requires Specific Reference Intervals in Pregnant Women

Eijun Nishihara and Takashi Akamizu

Published Online:14 Mar 2023doi.org/10.1089/ct.2023;35....

liebertpub.com/doi/10.1089/...

diogenes Is this a reasonable statement?

As compared with other assays, the ED-LC-MS/MS measurement is less influenced by the pregnancy-associated changes in serum proteins, including high TBG and low albumin (2), but reports lower FT4 levels during pregnancy (3), especially in the third trimester (4).

[diogenes Remembering]

Reading this, I fall between helpless laughter and incredulity. In 1989, I and others published in Clinical Chemistry a prospective paper using three different FT4 assays (none of which are mentioned here) which demonstrated that in the 1st trimester, FT4 levels and ranges were close to non pregnant ones and in the second and third, FT4 was 25% lower on average. After I had left the scene with new ideas going ahead, my colleagues produced new assays which said exactly the same thing. None of these is mentioned here either. We also found TSH in the first trimester lower than in the 2nd and 3rd, owing to HCG acting as a weak TSH in the first trimester. All this has been repeated time and again, with little or no reference to our pioneering findings. Talk about reinventing the wheel, but using poor spokes.

[helvella Administrator Thyroid UK in reply to diogenes]

Thanks - I thought you had a history in this area!