The present invention encompasses a method for performing an antibody-antigen assay using an ion-exchange technique prior to performing an antibody-antigen assay. Actives from protein-denaturing solutions are physically removed from the test sample, preferably by using an ion-exchange resin. The present invention also includes a method of performing an antibody-antigen assay, which does not use coating antibody on the sample holder. These methods for removing or eliminating interferences can be used in an ELISA to more effectively, efficiently and promptly screen formulations containing protein-denaturing compounds for efficacy against proteins in common allergens and detect and quantify such proteins.