Unbound-Analogue Methods for Free T4: A Note of Caution
- 8 July 1982
- journal article
- Published by Massachusetts Medical Society in New England Journal of Medicine
- Vol. 307 (2) , 126
- https://doi.org/10.1056/nejm198207083070220
Abstract
To the Editor: Two recently developed methods for determining free thyroxine (T4) — Amerlex free T4 and Clinical Assays GammaCoat one-step free T4 — use unidentified, labeled T4 analogues, which are said to show minor binding to plasma proteins. These methods rely on the assumption that antibody binding of a tracer that is not bound to plasma proteins will be inversely proportional to the sample free T4 concentration. It follows that any serum constituent that alters the amount of tracer available to compete with free T4 will influence the apparent free T4 . . .Keywords
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