Undetected coeliac disease is common, even in elderly people. Anti-transglutaminase, endomysial and deamidated gliadin antibody tests are sensitive and specific. Transglutaminase-specific IgA deposits in mucosal tissue provide the most accurate method of detecting early coeliac disease without villous atrophy. In refractory coeliac disease, the response to diet is lacking. Refractory disease is classified into types I and II. In type II, epithelial T-cells are negative for CD4/CD8 and there is monoclonal T-cell gamma-gene rearrangement, with an increased risk of lymphoma. The EU states that a 'gluten-free diet' should contain less than 20 mg, and a 'very low gluten diet' less than 100 mg, of gluten per kilogram.