[Diabetes mellitus--differential diagnosis]

Differentiation of the various forms of diabetes is necessary for therapeutic reasons. Typical signs of type 2 diabetes are age over 40, obesity, and other markers for metabolic syndrome, a positive famitory, gradual development of the classical symptoms, and no evidence of ketosis. It is important to distinguish this from LADA (latent autoimmune diabetes of adulthood), a form of type 1 diabetes mellitus. To establish this differential diagnosis antibody testing is employed. Antibody tests in patients with newly manifest diabetes make good sense when the clinical diagnosis is not unequivocal, that is, to distinguish it from type 2 diabetes, MODY diabetes, hereditary and secondary forms. At present, immunodiagnosis is used too often in unambiguous cases of type 1 diabetes, but too rarely in supposed type 2 diabetes. As a rule, LADA patients are GADA-positive. If MODY diabetes is suspected, a genetic examination is indicated. In patients with GDM, antibody testing with GADA makes sense, in particular in slim patients receiving insulin treatment, since these patients have a high risk for developing a postpartum diabetes already in the first years.