How useful are laboratory tests in diagnosing serious infections in febrile children?

Evaluating acute febrile illnesses in infants and young children is one of the most challenging diagnostic problems in primary care medicine. Most of these children have self limiting viral illnesses that will resolve quickly without medical intervention; serious bacterial infections occur rarely. In one large study of 15 781 febrile illnesses in children under 5 years, only 7.2% were found to have a serious bacterial infection.1 The search for a strategy to differentiate those children with serious bacterial infections from those with self limiting viral illnesses at the time of clinical presentation has met with limited success. In the linked systematic review (doi:10.1136/bmj.d3082), Van den Bruel and colleagues assess the diagnostic value of laboratory tests for the diagnosis of serious infections in children in ambulatory settings.2

Clinical guidelines for the management of febrile infants and toddlers up to 36 months of age …