“…Additionally, variants of the indirect ELISA principle, such as reverse enzyme immunoassay (REIA), sandwich ELISA, and multiple-dot ELISA, have also been explored [ 28 – 30 ]. Direct and indirect fluorescent antibody tests (FAT) [ 31 , 32 ], radioimmunoassays (RIA) [ 33 , 34 ], complement fixation tests [ 35 , 36 ], and double immunodiffusion tests [ 30 , 34 , 36 , 37 ], were employed until 2003, after which ELISA and western blot became the predominant techniques together with new technologies that appeared on the scene ( S4 Info ). Among these new technologies, the multiplex bead assay [ 38 ], peptide microarray immunoassays [ 39 , 40 ] and quantitative suspension array technology (qSAT) assays [ 41 , 42 ] represent examples of multiplex assays.…”