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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
For differentiating between Insulinoma and Sulfonylurea related hypoglycemia, the test which is useful is ?
assistant
The correct answer is  Surreptitious use of insulin or hypoglycemic agents like sulfonylureas may be difficult to distinguish from insulinomas. The combination of proinsulin levels (normal in exogenous insulin/hypoglycemic agent users), C-peptide levels (low in exogenous insulin users), antibodies to insulin (positive in exogenous insulin users), and measurement of sulfonylurea levels in serum or plasma will allow the correct diagnosis to be made. Reference : page 569 Harrison's Principles of Internal Medicine 19th edition