Spurious Conclusions on Analog Free Thyroxine Assay Performance

Autor:	John E.M. Midgley
Rok vydání:	2007
Předmět:	medicine.medical_specialty Endocrinology Chromatography medicine.diagnostic_test Chemistry Internal medicine Immunoassay Biochemistry (medical) Clinical Biochemistry medicine Free thyroxine Spurious relationship hormones hormone substitutes and hormone antagonists
Zdroj:	Clinical Chemistry. 53:1714-1714
ISSN:	1530-8561 0009-9147
DOI:	10.1373/clinchem.2007.090878
Popis:	I read with misgivings the recent communication by Fritz et al. (1) alleging that because under some circumstances an analog free thyroxine (FT4) immunoassay correlates total T4 and FT4 values, it does not measure FT4 but something akin to T4. I have shown repeatedly through mass action analyses (2)(3)(4) that many experiments, including the one reported by Fritz et al. (1) and others described in earlier papers(5)(6), cannot meaningfully address the working of any of these assays. Allegations of shortcomings cannot be substantiated if they depend on experiments using artificial T4 solutions in which serum T4-binding proteins are either lacking or are present at concentrations insufficient to prevent overlarge T4 abstraction by the assay antibody (conditions strictly invalid for FT4 measurements). The amount of antibody that can be used in analog FT4 assays having a radioactive probe is limited (3). Constraints on the stability of molecules radiolabeled …
Databáze:	OpenAIRE
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