A homogeneous immunoassay method and system for quantitative determination of total immunoglobulin E and specific antibody levels to a plurality of allergens, in which a relatively small sampling of blood is required. The method utilizes relatively small microparticles in aqueous suspension. The immunoassay procedure is an immunometric sandwich procedure preferably utilizing biotin-streptavidin signal amplification techniques and R-phycoerytherin fluorescent labels.