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How to use a controlled fast to investigate hypoglycaemia
  1. S Sreekantam1,
  2. M A Preece2,
  3. S Vijay1,
  4. J Raiman1,
  5. S Santra1
  1. 1Department of Metabolic Medicine, Birmingham Children's Hospital, Birmingham, UK
  2. 2Department of Newborn Screening and Biochemical Genetics, Birmingham Children's Hospital, Birmingham, UK
  1. Correspondence to Dr S Santra, Department of Metabolic Medicine, Birmingham Children's Hospital, Birmingham B4 6NH, UK; saikat.santra{at}


Controlled fasts can play a valuable role in the diagnosis and management of hypoglycaemia in paediatric clinical practice, but are no substitute for the collecting of appropriate critical samples at the time of hypoglycaemia for metabolic and endocrine studies. Fatty acid oxidation defects, hyperinsulinism and adrenal insufficiency should always be excluded prior to organising controlled fasts. Controlled fasts are safe if conducted in an experienced setting with strict protocols in place. Failure to adhere to protocol can defeat the purpose of the study and can potentially be dangerous. Proper planning in conjunction with the laboratory and close supervision by staff experienced in controlled fasts is crucial to ensure the best quality information is yielded from these procedures.

  • hypoglycaemia
  • controlled fast
  • fasting tolerance
  • Idiopathic ketotic hypoglycaemia
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  • Contributors SSr: written the article. SSa: contributed to design and presentation of the data, gave ideas for the scenarios, critically reviewed the paper and finalised it. JR: reviewed the clinical questions and also helped with the design and presentation of the data. SV: reviewed the paper. MAP: reviewed relevant literature, contributed to design and presentation of the data and offered ideas for the scenario.

  • Competing interests None declared.

  • Provenance and peer review Commissioned; externally peer reviewed.

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