['Hyperglycaemia is associated with increased mortality in critically ill patients. A number of studies have highlighted an association between increased variability of blood glucose (BG) concentration and mortality, supporting a survival disadvantage if BG homeostasis is lost. By exploring the longitudinal BG profile of individual children over time, this study investigates the importance of intact homeostasis early after admission to the paediatric intensive care unit (PICU).', 'Retrospective single-centre observational study in a large multi-specialty PICU in the UK. Children admitted between August 2003 and February 2006 were included unless they met exclusion criteria. Data were merged from the PICU clinical database and blood gas analyser database by means of a unique PICU identifier. BG was measured frequently on a blood gas analyser (Bayer Rapidlink). Primary outcome was 100-day mortality. BG parameters were investigated for possible associations with mortality.', 'A total of 1,763 patients were included (median age 1.1 years; IQR 0.1-5.8). Although admission BG was not associated with mortality, a survival advantage was found in children who showed a reduction in BG on day 1 relative to the admission BG value (p < 0.001). This remained statistically significant (p = 0.007) after adjusting for severity of illness.'] Is early change in blood glucose concentration an indicator of mortality in critically ill children?