Early signaling of bacteremia in patients who present to the department of emergency medicine with relatively low C-reactive protein (CRP) concentrations

•Bacteremia in hospitalized patients requires prompt administration of appropriate antibiotic therapy.•Various inflammatory biomarkers are used to aid in deciding if antibiotic treatment is warranted.•Low concentrations of inflammatory markers can mislead clinicians into thinking there isn’t an infection.•CRP velocity is shown to be superior to CRP alone and WBC in predicting bacteremia. Examiningthe usefulness of C-reactive protein velocity (CRPv) as an early biomarker for the presence of bacteraemia in patients presenting to the Department of Emergency Medicine with acute infection/inflammation and suspected bacteraemia. A retrospective study examining a cohort of patients who presented to the E.R and in whom blood cultures were taken. CRPv was calculated as the difference in mg/hour/litter between two consecutive CRP tests performed within 12 h. 256 patients were included in the cohort. Using CRPv in patients who at first presented with a relatively low (17.9 ≤ mg/L 1stquartile) CRP concentration, we found an AUC of 0.808 ± 0.038 (p