Fever is one of the most common reasons for infants to present to the emergency department (ED).1 Among febrile infants younger than 3 months presenting to EDs, approximately 5% to 9% will have urinary tract infections, 2% will have bacteremia, and less than 0.5% will have bacterial meningitis.2,3 Hereafter, these will be referred to as “the big 3” infections with the latter 2 infections termed invasive bacterial infections. We will avoid using the term serious bacterial infections for all 3, as this implies an equivalent level of severity.
Kuppermann N, Mahajan P. Role of Serum Procalcitonin in Identifying Young Febrile Infants With Invasive Bacterial InfectionsOne Step Closer to the Holy Grail? . JAMA Pediatr. 2016;170(1):17-18. doi:10.1001/jamapediatrics.2015.3267