—Of course Dr Goldman is correct. One reason that patients receiving oral agents get hypoglycemic is that the drug stimulates endogenous insulin. Thus, a low insulin level with hypoglycemia is only suggestive for surreptitious or exogenous insulin and not oral hypoglycemic agent abuse.I thank Dr Goldman for pointing out this error. The practical therapeutic point is that, given a patient with hypoglycemia and "normal" or "elevated" C peptide levels, a screening test for oral hypoglycemic agents should be done. If positive, this should be investigated further before the diagnosis of insulinoma is made.