As a junior doctor some years back, more than I can believe now, I remember the anxiety and anticipation I felt as I contacted a family who had taken their toddler home from accident and emergency after reassurance. A blood culture had then rapidly grown a meningococcus. The child was fine after readmission and treatment. It is a singular concern for any doctor dealing with a child presenting acutely with possible infection that they might miss severe bacterial sepsis. Those of us who have worked in paediatric intensive care will all have felt a shudder hearing stories from parents of children with serious illness that was not recognised. We may have looked at our own sick children at 3:00 am and remembered a parent's chilling phrase or description. Last winter H1N1 flu again reminded us just how hard it can be to get a diagnosis right.

The failure to recognise or a delay in recognising serious illness was one of the themes identified in ‘Why children die: a pilot study’, after the national confidential enquiry in 2008.1 The need to develop robust systems for identifying the seriously ill child was emphasised. We all understand that clinical experience has an important role to play.2,–,4 Experience, however, takes a long time and a good deal of work to acquire and is not infallible: ars …