Heterophilic Antibody (HA) interference in double-antibody sandwich reaction models can lead to false results due to non specific binding to capture and detection reagents. In particular, Human Anti-Mouse Antibody (HAMA) incidence rate is around 10% in immunodiagnostic assays. Other types of HA include, Heterophilic Antibody Goat Antibody (HAGA), Heterophilic Antibody Sheep Antibody (HASA), and Heterophilic Antibody Rabbit Antibody (HARA). The blocking reagent binds to the interferent antibody sufficiently to block its reaction with capture antibody or conjugated antibody. Synonyms: Heterophilic Immunoglobulin Blocking Reagent, Rheumatoid Factor blocking reagent, RF blocking reagent, HA blocking reagent.