Abstract
<title>Abstract</title> <p>Background Sepsis remains a leading cause of morbidity and mortality in children. Early and accurate diagnosis is critical for improving outcomes, yet current biomarkers like procalcitonin (PCT) and C-reactive protein (CRP) lack sufficient specificity. Osteopontin (OPN), a glycoprotein involved in inflammation and immune response, has shown promise as a biomarker in adult sepsis, but its value in the pediatric population remains unclear. Methods In this prospective cohort study, we measured serum OPN, PCT, and CRP levels in 108 children with sepsis, 77 children with common infections, and 65 healthy controls. The primary objective was to evaluate the diagnostic and prognostic performance of OPN for pediatric sepsis. Results Serum OPN levels were significantly elevated in children with sepsis compared to both common infection and healthy control groups (P < 0.001). Notably, OPN levels did not differ significantly between the common infection and healthy groups, highlighting its specificity for sepsis-related organ dysfunction. The area under the receiver operating characteristic curve (AUC) for OPN in diagnosing sepsis was 0.94 (95% CI: 0.91–0.98), which was superior to that of PCT (0.83) and CRP (0.76). At a cutoff of 132.8 ng/mL, OPN demonstrated a sensitivity of 85.2% and a remarkable specificity of 98.7%. While a single admission OPN measurement did not significantly predict 28-day mortality, longitudinal monitoring in a subgroup revealed that persistently elevated or rising OPN levels were associated with non-survival. Conclusions Serum OPN is a highly specific and sensitive biomarker for diagnosing pediatric sepsis, outperforming conventional markers. While a single measurement may not predict prognosis, dynamic monitoring of OPN levels shows potential for identifying patients at risk of adverse outcomes.</p>