This assay employs the competitive inhibition enzyme immunoassay technique. The microtiter plate provided in this kit has been pre-coated with an antibody specific to T4. Standards or samples are added to the appropriate microtiter plate wells with Biotin-conjugated T4. A competitive inhibition reaction is launched between T4 (Standards or samples) and Biotin-conjugated T4 with the pre-coated antibody specific for T4. The more amount of T4 in samples, the less antibody bound by Biotin-conjugated