Algorithm for diagnostic fasting study Algorithm for diagnostic fasting study. For children older than 2 years, start the fast following dinner or bedtime snack. For children less than 2 years, the fast may be started after a specified feeding. Point-of-care glucose should be monitored with the frequency based on rate of decline as well as patient age. For example, a neonate may experience a more rapid drop and should be monitored more frequently than an older child. Diagnostic samples should be obtained when the plasma glucose drops to ≤ 50 mg/dL. Laboratory tests are prioritized based on the differential diagnosis. After the critical specimens have been collected, if either congenital hyperinsulinism or growth hormone deficiency is suspected, a diagnostic glucagon challenge should be performed. After the final blood sample has been collected,10% dextrose should be administered parenterally while allowing the patient to eat. Blood glucose should be monitored every 10 to 15 minutes until it remains above 70 mg/dL. If, during the diagnostic fast, the patient displays a seizure or other form of altered mental status, the diagnostic blood samples should be promptly obtained followed immediately by a 2-mL/kg intravenous bolus of 10% dextrose and then a continuous infusion of parenteral dextrose. β-OHB, beta-hydroxybutyrate; IGFBP-1, insulin-like growth factor-binding protein-1; FFA, free fatty acid; AcAc, acetoacetate; NaF, sodium fluoride. Source: Hypoglycemia, Pediatric Practice: Endocrinology, 2e Citation: Kappy MS, Allen DB, Geffner ME. Pediatric Practice: Endocrinology, 2e; 2013 Available at: http://accesspediatrics.mhmedical.com/DownloadImage.aspx?image=/data/books/1082/kap_ch12_f005.png&sec=61465074&BookID=1082&ChapterSecID=61464984&imagename= Accessed: October 23, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved