The present enzyme-linked immuno sorbent assay (ELISA) is intended for the quantitative or qualitative determination of IgA antibodies in human serum, directed against a modified gliadin peptide (MGP). The immobilised antigen is a highly purified, synthetic peptide derivative. The test is fast (incubation time 30 / 30 / 30 minutes) and flexible (divisible solid phase, ready-to-use reagents). Six calibrators allow quantitative measurements; a negative and a positive control check the assay performance.