Diagnostic accuracy of PCT, IL-6, and MR-ProADM for early identification of sepsis in the emergency department

OBJECTIVE: To evaluate the diagnostic accuracy of the biomarkers procalcitonin (PCT), interleukin-6 (IL-6), and mid-regional pro-adrenomedullin (MR-ProADM), individually and in combination, for early detection of sepsis and septic shock during emergency department (ED) triage. MATERIALS AND METHODS: A retrospective observational study was conducted in adults presenting to the ED with triage levels 2 and 3 between December 2021 and July 2023. Blood samples were collected at admission, prior to any therapeutic intervention. Plasma concentrations of PCT, IL-6, and MR-ProADM were measured using CMIA or ELISA. Diagnostic accuracy was assessed using ROC curves and AUC analysis. RESULTS: A total of 248 patients were included (214 with sepsis and 34 non-septic controls). Simultaneous elevation of PCT, IL-6, and MR-ProADM was observed in 70% of septic patients compared with 3% of controls. Each biomarker showed high diagnostic accuracy for sepsis (AUROC >0.90). The combined assessment increased specificity and was strongly associated with sepsis and septic shock, with progressively higher odds as the number of elevated biomarkers increased. Higher biomarker burden was also associated with indicators of greater clinical severity, including higher SOFA scores and ICU admission. CONCLUSIONS: Combined measurement of PCT, IL-6, and MR-ProADM at ED triage, before therapeutic intervention, improves early identification of patients with sepsis and provides relevant information on initial disease severity. This multiplex platform approach may support clinical prioritization and protocol activation in the ED.