INS and pancreatic insulinoma: Despite the low plasma glucose, her insulin (7.30 μU/mL: normal range, < 18.7 μU/mL) and C-peptide (1.97 ng/mL: normal range, 0.61–2.09 ng/mL) levels were inappropriately high, and the blood glucose level was increased to 109 mg /dL at 20 min after an intravenous glucagon infusion, all of which findings are consistent with insulinoma.