Identifying patients with bacterial infections using a combination of C-reactive protein, procalcitonin, TRAIL, and IP-10 in the emergency department: a prospective observational cohort study.

OBJECTIVES: The aim was to effectively reduce the unnecessary use of broad spectrum antibiotics in the emergency department (ED), patients with bacterial infections need to be identified accurately. We investigated the diagnostic value of a combination of biomarkers for bacterial infections, C-reactive protein (CRP), and procalcitonin (PCT), together with biomarkers for viral infections, tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), and interferon-gamma-induced protein-10 (IP-10), in identifying suspected and confirmed bacterial infections in a general ED population with fever.

METHODS: This is a sub-study in the HiTEMP cohort. Patients with fever were included during ED triage, and blood samples were obtained. Using both diagnostics and expert panel analysis, all patients were classified as having either suspected or confirmed bacterial infections, or non-bacterial disease. Using multivariable logistic regression analysis, three biomarker models were analysed: model 1, CRP, TRAIL, IP-10; model 2, PCT, TRAIL, IP-10; and model 3, CRP, PCT, TRAIL, IP-10.

RESULTS: A total of 315 patients were included, of whom 228 patients had a suspected or confirmed bacterial infection. The areas under the curve for the combined models were the following: model 1, 0.730 (95% CI 0.665-0.795); model 2, 0.748 (95% CI 0.685-0.811); and model 3, 0.767(95% CI 0.704-0.829).

CONCLUSIONS: These findings show that a combination of CRP, PCT, TRAIL and IP-10 can identify bacterial infections with higher accuracy than single biomarkers and combinations of a single bacterial biomarkers combined with TRAIL and IP-10.