Abstract: A method, particularly an enzyme-linked immunosorbent assay (ELISA), for the in-vitro detection of A? autoantibodies in human serum and/or plasma contains the following steps: preparing an antigen-coated solid phase; incubating the solid phase with a blocking solution; incubating the solid phase with a sample to be examined; immunological detection of the A? autoantibodies on the solid phase; and reading the detected results of the solid phase using a reading tool. According to the invention, the preparation of the antigen-coated solid phase advantageously includes incubating the solid phase with a coating solution in which the antigen is dissolved, said antigen having a peptide sequence selected from the group SEQ ID No. 1, SEQ ID No. 2 or SEQ ID No. 3.