The highly sensitive tests Anti-Gliadin (GAF-3X) ELISA serve for the determination of the celiac disease related fraction of gliadin antibodies in the serological diagnosis of gluten-sensitive enteropathy (celiac disease, non-tropical sprue) and Duhring’s dermatitis herpetiformis. Celiac disease is an autoimmune disease which occurs in predisposed individuals as a reaction to gluten sensitivity. After absorption in the lamina propria of the intestinal mucosa gliadin is deamidated by tissue transglutaminase (tTG). In this process particular glutamine residues are replaced by glutamic acid residues. In individuals with a genetic predisposition pieces (peptides) of gliadin modified (reconstructed) in this way bind to e.g. HLADQ2/8 molecules of the antigen presenting cells and are presented to helper T cells. An extensive immune reaction is triggered, causing pathological tissue changes, particularly damage to the small intestine. Components of this immune reaction are antibodies against endomysium or tTG and against the deamidated gliadin generated by tTG. The frequency of diagnosed coeliac disease amounts to around 1:300 in western Ireland, Italy, the USA, the Middle East, India and Cuba, around 1:1,000 in Germany and Austria and around 1:2,000 to 1:4,500 in other European countries. The clinical symptoms comprise fatigue (78%), borborygmus (72%), abdominal pain (64%), diarrhoea (56%), effects of malabsorption (44%) with weight loss, anaemia and growth retardation in children, vomiting (16%), constipation (12%) and bone pains (12%). Some patients with glutensensitive enteropathy also suffer from Duhring's dermatitis herpetiformis (10%), a chronic skin disease accompanied by the formation of blisters. In a prolonged course, mainly in adults, the risk of melanoma, particularly intestinal T-cell lymphoma, is about 10%