Abstract: The method of measuring circulating antigens or antibodies by using a ligand labeled specific antigen or ligand labeled specific antibody chemically attached to a soluble matrix or backbone, a differently labeled anti-antigen or anti-antibody and a solid phase anti-ligand directed at the ligand attached to the specific antigen or specific antibody. This is achieved by either one or two analytical schemes:(a) Reacting a patient sample with a ligand labeled specific antigen or a ligand labeled specific antibody in the liquid phase in the presence of a differently labeled specific anti-antigen or labeled specific anti-antibody. This immunological complex is reacted with an immobilized anti-ligand on a solid support which is directed against the ligand attached to the specific antigen or antibody through the liquid matrix. Subsequently the solid phase is washed and checked for the label on the anti-antigen or anti-antibody which is directly proportional to the concentration of specific antigen or antibody.