Thresholds for hypoglycaemic screening-a cause for concern?

23 Jul 2018

The new Framework for Practice highlights the limited evidence for our current clinical practice (1). It is helpful in emphasising the importance of accurate measurement of glucose concentrations, listening to the concerns of parents and acknowledging that untreated hypoglycaemia can have devastating longterm consequences. However we have the following concerns: Screening thresholds The Framework recommends lowering a commonly accepted screening threshold in infants considered to be at risk of hypoglycaemia to a level that at any other time of life would be considered harmful. It fails to acknowledge the differences between screening and diagnostic thresholds; something neonatologists are very familiar with in the management of babies with jaundice. Phototherapy is provided to many babies with bilirubin levels well below a harmful level to prevent a harmful level being reached. Screening interventions are intended to prevent harmful events. Such thresholds will inevitably mean many individuals are treated ‘unnecessarily’ to avoid the risk of significant harm. In 2000 Cornblath et al published guidance on ‘operational thresholds’ in keeping with the current BAPM framework (2). However, and possibly reflecting concerns about the lack of evidence for the safety of this lower operational threshold, in 2017 in the UK, >80% of neonatal units still used <2.6mmol/ as their defined hypoglycaemic threshold (3). A threshold of <2.6mmol/l provides an opportunity for intervention before damaging neuroglycopaenia occurs.