The conjugated goat anti-mouse polymer horseradish peroxidase (HRP) and the conjugated goat anti-rabbit polymer alkaline phosphatase (AP) secondary antibodies react with both heavy and light chains on mouse and rabbit IgG. The innovative HRP-and AP-polymerization technology provides a significant increase in staining sensitivity when compared to conventional HRP- or AP-conjugated secondary antibodies. Avidin-biotin blocking procedures are not necessary when using the multiplex conjugated secondary antibodies. The intelliPATHTM Multiplex Secondary Reagent 2 is designed for use on the intelliPATH automated stainer, in conjunction with a cocktail consisting of a mouse monoclonal antibody and a rabbit polyclonal/monoclonal antibody. This method provides a rapid, 4-step staining procedure that can be completed in less than two hours.