Time-Resolved Fluorescence Immunoassay of Thyroxine in Serum: Immobilized Antigen Approach

✍ Scribed by Fengbo Wu; Yongyuan Xu; Tao Xu; Yanzheng Wang; Shiquan Han

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 71 KB
• Volume: 276
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1006/abio.1999.4342

✦ Synopsis

With T 4 -bovine IgG as a solid-phase antigen, we have developed a direct competitive-type immunoassay for serum total thyroxine (TT 4 ), which depends on the competitive distribution of europium-labeled anti-T 4 monoclonal antibody between solid-phasebound T 4 and the T 4 in the sample or standard. The captured fraction of the tracer was measured after a dissociation-enhancement step. Four different T 4 protein conjugates were synthesized, of which T 4 -bovine IgG was selected as the most favorable for the preparation of solid-phase antigen. The sensitivity was 3.5 ng/ml with a sample volume of 20 l. T 4 values ob- tained by this procedure agreed well with those obtained by RIA (r ‫؍‬ 0.967, n ‫؍‬ 38) and EG&G Wallac TRFIA (r ‫؍‬ 0.926, n ‫؍‬ 64). All other quality criteria was also fulfilled with respect to precision, accuracy, and dynamic range.