INS and Hypoglycemia: The suspected diagnosis based on the presence of Whipple’s triad needs to be verified with a method successfully detecting 99% of the cases, namely the up to 72 hours long fasting test with concurrent measurements of beta-cell polypeptides (insulin >4 μU/mL, C-peptide >0.2 nmol/L and proinsulin >5 pmol/L) at the time of hypoglycemia (3, 7).