Use of Nonspecific F(ab′)2 and Inactive -D-Galactosidase to Reduce the Nonspecific Binding of Anti-Ferritin Fab′--D-Galactosidase Conjugate in Two-Site Enzyme Immunoassay for Ferritin

The nonspecific binding of rabbit anti-ferritin Fab′-B-D-galactosidase conjugate to rabbit anti-ferritin IgG-coated polystyrene balls in two-site enzyme immunoassay for ferritin was reduced to various extents by the presence of nonspecific rabbit F(ab′)2, inactive -D-galactosidase and related substances with only small decreases in the specific binding, and the detection limit of ferritin was improved up to 10-fold. The use of nonspecific F(ab′)2, inactive -D-galactosidase and related substances was suggested to be useful for improving the detection limit of other antigens.