Enhanced Detection of immunoglobulin binding by a modified ELISA.

A modification of the ELISA assay is described which significantly enhances the chromogenic signal, thereby increasing the sensitivity of the assay. This enhanced ELISA employs a protein A-HRP conjugate to detect antibody bound to antigen coated polystyrene plates, followed by incubation with an anti-protein A-HRP conjugate as the amplification step. This enhanced ELISA is rapid, inexpensive, uses commercially available reagents and maintains the low background and high specificity of standard ELISA.