Serum ferritin as an adjunctive marker of dengue severity in the pediatric emergency department

Introduction Hyperferritinemia has been described as a potential marker of disease severity in various conditions, including dengue infection, where it has been associated with worse clinical outcomes. Objective To evaluate the utility of serum ferritin levels in discriminating dengue with warning signs or severe dengue. Materials and methods This single-center prospective cohort study evaluated ferritin levels in relation to disease severity in patients aged 1 month to 17 years. Patients were classified into two groups: non-severe dengue (group 1, without warning signs) and dengue with warning signs or severe dengue (group 2). All cases were laboratory-confirmed by antigen detection or serology and were evaluated in the Pediatric Emergency Department between December 2023 and May 2024. Results A total of 142 patients were included, of whom 42.2% were classified as group 1 and 57.8% as group 2. Median ferritin levels were significantly higher in group 2 compared with group 1 841.5 ng/mL (IQR: 244–1,747) vs. 261.5 ng/mL (IQR: 130–645.5); p = 0.001. A ferritin cutoff value of 382 ng/mL was associated with dengue with warning signs or severe dengue (39% vs. 14%; p 0.001; RR: 4.0; 95% CI: 2.0–8.2). The area under the receiver operating characteristic (ROC) curve was 0.67 (95% CI: 0.57–0.75), with a sensitivity and specificity of 67%, a positive predictive value of 60%, and a negative predictive value of 73%. The positive and negative likelihood ratios were 2.0 and 0.49, respectively. Conclusion Higher ferritin levels were observed in patients with dengue with warning signs or severe dengue. Although a cutoff value of ≥382 ng/mL was associated with this composite outcome, its discriminatory performance was limited. Ferritin may serve as an adjunctive biomarker but should not be used as a standalone predictor of disease severity in pediatric dengue.