Test Details: Insulin is a hormone produced by the pancreas. During the process of making insulin, pancreas produces C-peptide as well. This test is useful in various conditions, like; diagnosis of factitious hypoglycaemia due to surreptitious administration of insulin, evaluation of possible insulinoma, surrogate measure for the absence or presence of physiological suppressibility of endogenous insulin secretion during diagnostic insulin-induced hypoglycaemia (C-peptide suppression test), assessing insulin secretory reserve in selected diabetic patients who either have insulin autoantibodies or who are receiving insulin therapy, assessing residual endogenous insulin secretory reserve, monitoring pancreatic and islet cell transplant function, monitoring immunomodulatory therapy aimed at slowing progression of preclinical, or very early stage type 1 diabetes mellitus.