All of our biotinylated anti-immunoglobulins have been prepared to provide optimal results in solid-phase assays, cell sorting, and immunohistochemical staining. Animals are hyperimmunized with an injection regimen that selectively produces high affinity antibodies. We also employ a special technique in our affinity chromatography procedure that removes any low affinity antibodies which may be present. We biotin label the antibodies optimally, so that no insoluble products or antibodies with high nonspecific binding properties are present. Cross-reactivities that are likely to interfere with specific labeling are removed by solid-phase adsorption techniques. The final product is then subjected to rigorous quality control assays including immunodiffusion, solid-phase enzyme immunoassays, gel electrophoresis, and solid-phase binding assays. Cross-reactivity data are included in the specification sheet that accompanies the product.