Assay of free thyroxine in serum: a preliminary comparison of three commercial kits
Tuttlebee, J.W.
Medical Laboratory Sciences 38(2): 85-90
1981
ISSN/ISBN: 0308-3616 PMID: 7339415 Document Number: 174448
Free thyroxine was measured in various groups of subjects using a commercial kit and selected representative samples spanning a wide range of free thyroxine concentrations were re-assayed using 2 other manufacturers' kits which showed good correlation with the original results despite the different principles on which the kits are based (r = 0.95 and 0.91, respectively). All kits showed good intraassay precision. The interassay precision (n = 12) for the original kit was 13.1%. A 95% Gaussian normal range for this method was established of 14.0-26.4 pmol/l (n = 62). Experimental data on this are cited to support the revised calculation which has now been adopted by the manufacturers.