Diagnosis and classification of diabetes mellitus

The diagnosis of diabetes mellitus is established by history, physical examination, and measurements of serum or plasma glucose concentrations under specific conditions. This disorder represents the final common expression of diverse etiologies which are incompletely understood. The treatable causes of diabetes should be identified, and the appropriate therapy initiated. Distinguishing Type I and Type II diabetes is often useful, but not a necessary prerequisite for initiating therapy. As we begin to understand the underlying causes of diabetes, our emphasis is likely to shift from a diagnosis based on metabolic characteristics to a diagnosis based on etiology.