Diagnostic Utility of Creatine Kinase and IL-10 in Early Discrimination Between Pediatric Influenza A (H1N1) and Adenovirus Infections

Background Differentiating influenza, A (H1N1) from adenovirus infection in children remains challenging during concurrent outbreaks due to overlapping clinical features. Rapid, reliable biomarkers are needed to guide early management. Methods We retrospectively reviewed clinical and laboratory data from 307 children with laboratory-confirmed influenza A (H1N1) and 118 with adenovirus infection admitted to the Second Affiliated Hospital of Wenzhou Medical University between May and September 2024. Demographics and serum levels of creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), interleukin-8 (IL-8), and interleukin-10 (IL-10) were compared. Univariate and multivariate logistic regression models were used to assess discriminative performance. Diagnostic accuracy was evaluated using area under the receiver operating characteristic curve (AUC), with optimal cut-offs determined by Youden’s index. Results Children with H1N1 were older than those with adenovirus infection (5.67 ± 3.45 vs. 3.82 ± 1.94 years; P < 0.05); sex distribution did not differ significantly. Among single markers, IL-10 showed the highest AUC for identifying H1N1 (0.922; 95% CI: 0.870–0.974), followed by CK (0.915; 0.869–0.961) and LDH (0.880; 0.818–0.942). A combined model of CK and IL-10 yielded an AUC of 0.965 (95% CI: 0.938–0.993), with sensitivity of 90.0% and specificity of 94.1%, outperforming any individual marker. Conclusions The combination of serum CK and IL-10 demonstrates high diagnostic accuracy for early differentiation of influenza A (H1N1) from adenovirus infection in children. This dual-marker approach may support timely clinical decision-making and pathogen-directed management in acute respiratory illness.