[How I explore ... the different forms of sugar diabetes: clinical and biological differental diagnosis].

Owing to the increasing prevalence of diabetes mellitus and the various aspects of this disease, we present a practical approach which allows the clinician to more easily differentiate type 1 diabetes, type 2 diabetes and secondary diabetes of pancreatic origin, i.e. the most common forms of diabetes mellitus. Such an approach uses simple diagnostic criteria, based upon both clinical characteristics (family history, personal history, clinical presentation) and biological markers (C-peptide, autoantibodies,...). A right diagnosis should allow to optimize the management of the diabetic patient.