Figure 2. Hypoglycemia diagnosis based on plasma metabolic fuel responses. Measurement of lactate as a gluconeogenic substrate, FFA from adipose tissue lipolysis, and BOHB at the time of hypoglycemia segregates major groups of hypoglycemia disorders. FFA, free fatty acids; GH, growth hormone; HCO3, bicarbonate; BOHB, beta-hydroxybutyrate. Adapted from Thornton PS, Stanley CA, De Leon DD, Harris D, Haymond MW, Hussain K, Levitsky LL, Murad MH, Rozance PJ, Simmons RA, Sperling MA, Weinstein DA, White NH, Wolfsdorf JI, Pediatric Endocrine S. Recommendations from the Pediatric Endocrine Society for Evaluation and Management of Persistent Hypoglycemia in Neonates, Infants, and Children. J Pediatr. 2015;167(2):238-245 (21).