This secondary antibody is affinity-purified and is suitable to detect rabbit antibodies used in ELISA. Polymer-HRP conjugation enhances the sensitivity and reduces the background of the detection. First, a primary antibody of rabbit origin is bound to a target antigen. After a brief wash, Polymer-HRP-conjugated goat anti-rabbit IgG secondary antibody is applied to form a complex with the primary antibody. After another brief wash, HRP substrates such as luminol or 3,3'-diaminobenzidine (DAB) are added to generate detectable chemiluminescence or insoluble colors.