A method for preventing or inhibiting non-specific binding reactions between a detection reagent and an antigen in an immunological assay is described. The method involves using tetrameric antibody complexes that can bind to the antigen and are comprised of two monoclonal antibodies of a first animal species linked to two monoclonal antibodies of a second animal species that can bind the antibodies of the first animal species. Preferably, the antigen is an Fc Receptor and the method reduces the binding of a detection antibody with Fc receptors present on the surface of many cells.