Background Although the topic of identifying febrile children at risk of serious infections has been addressed by numerous research groups, identified predictors remain diverse and implementation of results in routine practice has been limited. The aim of this paper is to discuss the problems and challenges in advancing diagnostic research in febrile children.

Methods The characteristics and results of 35 studies identified from a systematic review on predictors for febrile children were evaluated.

Results Current diagnostic research is mainly performed in subpopulations, defined by age and temperature limits and in paediatric emergency settings, ignoring the role of primary care. It is characterised by a dichotomous approach of outcomes and a wide variability of potential predictors. Validation of results to other settings and impact studies of prediction rules on patient outcomes are scarce. In designing diagnostic studies on children suspected of serious infections focus is needed on all clinically relevant populations within the spectrum of primary care and emergency department settings. Consensus is also needed on the definition of fever, the concept of serious infection and the set of predictors to focus on. The heterogeneity of patients in different settings and countries stress the need for continuous updating of prediction rules in routine practice. Broad validation in different clinical settings and countries and impact analysis in routine care is essential.

Conclusions Scientists in the field of diagnosis of serious infection in children must agree on core design features to be incorporated in all studies in the area of diagnostic research in febrile children. This will improve evidence from future studies, and their generalisability and implementation in routine practice.