INS and hyperinsulinemic hypoglycemia: A 72-hour fast confirmed hyperinsulinemic hypoglycemia at 26 hours (glucose 36 mg/dL, insulin 10.3 mIU/L [normal range: 2.6–25 mIU/L], proinsulin 21.7 pmol/L [normal range: ≤21.7 pmol/L], C-peptide 2.3 μg/dL [normal range: 1.1–4.4 μg/dL], beta hydroxybutyric acid 0.06 mmol/L [normal range: 0.02–0.27 mmol/L], negative sulfonylurea screen, cortisol 28.9 μg/dL [normal range 6.2–19.4 μg/dL]).