Glod standard test for insulinoma: (A) 72 hr fasting test, (B) Plasma insulin levels, (C) C-peptide levels, (D) Low glucose levels < 30 mg\/dl
Answer is A. A fasting test that may last for up to 72 hrs is regarded as the most sensitive test.Usually , insulin, pro insulin, C-peptide and blood glucose are measured in 1- to 2-hr intervals to demonstrate inappropriately high secretion of insulin on relation to blood glucose. About 80% of insulinomas are diagnosed by this test,most of them in first 24 hrs . Bailey & Love ,26th,788