Serum Procalcitonin and Ferritin as Predictive Markers of Severity of Bacterial Infection in Pediatric Patients with Lower Respiratory Tract Infections

Abstract

Background: Lower respiratory tract infections (LRTIs), mainly community acquired pneumonia (CAP), are a main etiology of hospitalization and death in children under five years, with bacterial and viral pathogens being prevalent causes, with biomarkers like procalcitonin and serum ferritin serving as valuable predictors of disease severity and outcomes. Objective: To assess the prognostic and diagnostic value of serum procalcitonin and ferritin in pediatric cases had LRTIs and evaluate their role as predictors of disease severity and correlation with clinical outcomes. Methods: This cross-sectional research has been performed on 100 children admitted to Pediatric department and pediatric intensive care unit (PICU) at October 6 University hospital due to chest infection, during the period from January 2025 to December 2025. Results: Procalcitonin and serum ferritin were significantly higher in severe cases, positive cultures, and PICU admissions. ROC analysis showed procalcitonin had the highest predictive value for bacterial infections (AUC 0.980) at cutoff value of 2.6 nanogram per milliliters with sensitivity = 95% and specificity = 93.7%, followed by ferritin/procalcitonin ratio (AUC=0.958) with a cutoff value of 190, sensitivity = 89.6% and specificity= 92%. Serum ferritin showed (AUC=0.872) with a cutoff value of 175 with sensitivity = 95% and specificity= 71%, while CRP was not significant. Procalcitonin showed high prediction for PICU admission (AUC 0.972), and mortality (AUC 0.885). Ferritin and ferritin/procalcitonin ratio also showed good predictive performance. Conclusion: Procalcitonin and serum ferritin were higher, while ferritin/procalcitonin ratio was lower in severe cases, positive blood cultures, PICU admission, mechanical ventilated patients and in non-survivors. Procalcitonin is a good predictor for bacterial infection, PICU admission, and mortality, followed by ferritin/procalcitonin ratio and serum ferritin.