Measurement of IL-6 as an Inflammatory Biomarker in Early Detection of Sepsis Among Trauma ICU Patients

Abstract

Background: Sepsis is a life-threatening complication among trauma patients admitted to intensive care units, and early diagnosis remains challenging due to overlap between post-traumatic systemic inflammation and infection-related immune responses. Interleukin-6 (IL-6), a pro-inflammatory cytokine released rapidly after tissue injury or infection, has been proposed as a potential early biomarker for identifying sepsis in critically injured patients. Objective: To evaluate the diagnostic performance of serum IL-6 measured within 24 hours of ICU admission for early identification of sepsis among trauma ICU patients. Methods: A prospective observational diagnostic accuracy study was conducted in a tertiary care trauma ICU between March and December 2025. A total of 150 adult trauma patients were enrolled using consecutive sampling. Serum IL-6 levels were measured within 24 hours of admission using chemiluminescent immunoassay. Sepsis diagnosis was established according to Sepsis-3 criteria using clinical evaluation, microbiological findings, and organ dysfunction assessment. Receiver operating characteristic analysis was performed to determine the optimal IL-6 threshold and diagnostic accuracy parameters. Results: Among the 150 patients, 144 (96.0%) exhibited elevated IL-6 levels (>50 pg/mL), with a mean concentration of 125 ± 40 pg/mL. ROC analysis demonstrated excellent discriminative ability with an area under the curve of 0.91 (95% CI: 0.85–0.96). The optimal IL-6 cut-off value of 52 pg/mL yielded sensitivity of 93.2%, specificity of 81.4%, positive predictive value of 89.6%, and negative predictive value of 87.5%. Elevated IL-6 levels were consistently observed across age groups and genders. Conclusion: Serum IL-6 measured early after ICU admission demonstrates high diagnostic accuracy for identifying sepsis in trauma patients and may serve as a valuable biomarker for early detection and clinical decision-making in trauma ICU settings. Keywords: Interleukin-6, Sepsis, Trauma ICU, Biomarker, Inflammation, Early detection, ROC analysis.