The invention concerns a method for the immunological determination of a
specific antibody in a sample liquid in which the sample liquid is
incubated in the presence of a solid phase with two antigens directed
against the antibody to be determined of which the first antigen carries
at least one marker group and the second antigen is (a) bound to the
solid phase or (b) is present in a form capable of binding to the solid
phase and the antibody to be determined is detected by determining the
marker group in the solid phase or/and in the liquid phase characterized
in that at least one of the two antigens contains several epitope regions
which react with the antibody to be determined.