| abstract |
An immunoassay process for quantitative analysis of an analyte antigen (or analyte antibody) in an aqueous liquid sample. In the first step, the analyte antigen (or analyte antibody) is allowed to react with an antibody (or antigen) in competition with a known quantity of a labelled antigen (or labelled antibody), the antibody (or antigen) being carried by water-insoluble microparticles in the immobilized state. In the second step, the reaction mixture is spotted on a top porous layer of an integral multi-layered analysis element which includes the top porous layer, an intermediate detection layer and a bottom water-impermeable and transparent support. The top porous layer permeates aqueous solution and has pores sufficiently small to trap all of the microparticles carrying the antibodies (or antigens) bound to the analyte antigen (or analyte antibody) and bound to the labelled antigen (or labelled antibody). Thus, the free labelled antigen is allowed to pass through the top porous layer and migrate to the detection layer. In the third step, the quantity of the marker labelling to the labelled antigen (or labelled antibody) which has not been bound to the immobilized antibody (immobilized antigen) is determined. |