Fever in the new millennium: A review of recent studies of markers of serious bacterial infection in febrile children

Purpose of review: Evaluation of a febrile infant or child for serious bacterial infections (SBI) can be a challenging task; there is no single reliable predictor of SBI in infants. This review examines some of the recent work evaluating the usefulness of indicators for SBI, such as white blood cell count (WBC). C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6). Recent findings: While WBC is traditionally used as an indicator of serious infection, it appears to be the least specific and sensitive test in children. CRP and PCT are the most promising, but neither is an ideal single indicator by itself, especially in infants. There has been very limited experience with PCT in this country, however. IL-6 is more useful than WBC but less accurate than either CRP or PCT. Summary: Much progress has been made in recent years in finding more accurate indicators of SBI than WBC. However, while recent developments have given clinicians some new tools in evaluating febrile infants and children, it remains a formidable undertaking. In the especially vulnerable infant population, the holy grail of a single ideal SBI indicator remains elusive.