What is the best way to distinguish type 1 and 2 diabetes?

Abstract

No clinical characteristic or diagnostic test is available to readily distinguish type 1 from type 2 diabetes mellitus. Although C-peptide levels, autoantibodies, and adiponectin-to-leptin ratios show some utility, they do not yet have a standard diagnostic role; research on the pathophysiology of diabetes suggests that the classic type 1 and type 2 distinctions may not be appropriate for all patients (strength of recommendation: C, based on expert opinion).