Diagnostic markers of acute infections in infants aged 1 week to 3 months: a retrospective cohort study.

Objective: History and physical examination do not reliably exclude serious bacterial infections (SBIs) in infants. We examined potential markers of SBI in young febrile infants.

Design: We reviewed white cell count (WBC), absolute neutrophil count (ANC), neutrophil to lymphocyte count ratio (NLR) and C reactive protein (CRP) in infants aged 1 week to 90 days, admitted for fever to one medical centre during 2012-2014.