Immunoassay method for thyroxine that uses a sandwich with a double-antibody system and forms a hormonal sandwich is most similar to ELISA in which format?

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A sandwich immunoassay uses two antibodies that bind different epitopes on the same target, forming a sandwich around the analyte and producing a signal via an enzyme label on the detector antibody, much like ELISA. For thyroxine described in this way, the format that best mirrors ELISA is the microparticle enzyme immunoassay. In MEIA, the assay uses microparticles with a capture antibody and a second enzyme-labeled antibody that binds the analyte, generating a signal in a manner very similar to a sandwich ELISA readout. The other options rely on competitive or non-sandwich formats (for example, fluorescent polarization or inhibition assays) and do not replicate the two-antibody sandwich with enzymatic detection characteristic of ELISA.