Abstract: The present invention is a method useful for the detection of bloodgroup antigens and antibodies. The method of the present invention is envisioned for two types of assays: a direct assay and an indirect assay. The direct assay comprises adding a sample of erythrocytes to a reaction tube charged with two layers of immunoreactive particles, a first layer, preferably Sepharose, having Protein G coupled to the surface of those particles and a second layer, preferably Sephacryl S-200, having Protein A coupled to those particles in a buffer solution. Antibodies specific for the bloodgroup antigens tested for are coupled to the Protein G. The reaction tube is then centrifuged for a time sufficient to force to the bottom of the reaction tube erythrocytes that do not attach to the antibodies.

Abstract: The present invention is a method and apparatus useful for the detection of bloodgroup antigens and antibodies. There are two preferred embodiments of the method: a direct assay and an indirect assay. The direct assay comprises adding a sample of erythrocytes to a reaction tube charged with a column of immunoreactive particles having an immunoglobulin binding ligand selected from the group consisting of Protein A, Protein G, Protein A/G or a universal kappa light chain binding protein coupled to the surface of the particles. Antibodies specific for bloodgroup antigens tested for are coupled to the ligand on the particles. The reaction tube is then centrifuged for a time sufficient to force to the bottom of the reaction tube erythrocytes that do not attach to the antibodies on the particles.