A 30 year old female presented with complaints of increased thirst & polyuria. Her random plasma glucose is 230 mg/dL confirms the diagnosis of diabetes mellitus. Which of the following tests differentiates type 1 diabetes from type 2?

Islet cell antibodies directed against GAD, insulin, IA/ICA-512, and ZnT-8 represents autoimmune process in type 1 diabetes. GAD-65 autoantibodies are widely available and can demonstrate antibodies in >85% of patients. HLA DR3 preference exist for type 1 diabetes but most individuals with predisposing halotypes do not develop disease. In early type 1 diabetes, some residual insulin can be present in plasma thus it is not useful to differentiate the two conditions Polymorphism of the peroxisome proliferator activated receptor g-2 is associated with type 2 diabetes but cannot distinguish the two conditions.