Immunoassay blockers are used in diagnostic assays to reduce non-specific binding and other interference that can lead to false-positive results. Specifically, interference from human anti-mouse antibodies (HAMA), rheumatoid factor (RH), and heterophilic antibodies (HA) are a major concern in both paired monoclonal sandwich assays and competitive assays. Specialized blockers are required in these assays to reduce any interference and to ensure the assay's accuracy.