A novel enzyme immunoassay for total thyroxine using immobilized antibodies and hydrophobic chromatography purified thyroxine-peroxidase conjugate.
A new and simple competitive enzyme immunoassay method for the measurement of total thyroxine in serum is described. Anti-thyroxine antibodies, raised in sheep with a bovine serum albumin-thyroxine conjugate prepared with carbodiimide as coupling initiator, were physically adsorbed onto a large surface area polypropylene support. Competition occurred between thyroxine in the sample and a thyroxine-peroxidase conjugate prepared with a glutaraldehyde spacer and further purified by octyl Sepharose hydrophobic chromatography. The entire assay was performed in 2 h with a useful range of 10-300 micrograms/l. The coefficients of variation ranged from 6.9 to 12% and good agreement (r = 0.93-0.97) was found between this method and 2 radioimmunoassays on 71 serum samples having well distributed thyroxine values.
D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D002847:Chromatography, Agarose; D003429:Cross Reactions; D006735:Horseradish Peroxidase; D006801:Humans; D007124:Immunoenzyme Techniques / Q000295:instrumentation; D007074:Immunoglobulin G / Q000276:immunology; D012685:Sepharose / Q000031:analogs & derivatives; D012756:Sheep / Q000276:immunology; D013974:Thyroxine / Q000097:blood*
D007074:Immunoglobulin G; C027176:octyl-sepharose CL-4B; D012685:Sepharose; D006735:Horseradish Peroxidase; D013974:Thyroxine