Routine blood parameters as auxiliary diagnostic tools for infection in children.

Recently, the incidence of () infection in children has been increasing annually. Early differential diagnosis of infection can not only avoid the abuse of antibiotics, but also is essential for early treatment and reduction of transmission. The change of routine blood parameters may have important clinical significance for the diagnosis of infection, but it has not been reported so far. This study aims to establish a predictive model for infection and explore the changes and clinical value of routine blood parameters in children with infection, serving as auxiliary indicators for the diagnosis and differentiation of clinical infection. A total of 770 paediatric patients with respiratory tract infections were enrolled in this study, including 360 in the group, 40 in the SARS-CoV-2 group, 200 in the influenza A virus group, and 170 in the control group. The differences of routine blood parameters among all groups were compared, and risk factors were analysed using multivariate logistics analysis, and the diagnostic efficacy of differential indicators using ROC curves. This study revealed that Mono% (OR: 3.411; 95% CI: 1.638-7.102; =0.001) was independent risk factor associated with infection, and Mono% (AUC=0.786, the optimal cutoff at 7.8%) had a good discriminative ability between patients with infection and healthy individuals. Additionally, Mono% (OR: 0.424; 95% CI: 0.231-0.781; =0.006) and Lymp% (OR: 0.430; 95% CI: 0.246-0.753; =0.003) were independent risk factors for distinguishing infection from influenza A virus infection, and the Lymp% (AUC=0.786, the optimal cutoff at 22.1%) and Net% (AUC=0.761, the optimal cutoff at 65.2%) had good discriminative abilities between infection and influenza A infection. Furthermore, platelet distribution width (OR: 0.680; 95% CI: 0.538-0.858; =0.001) was independent risk factor for distinguishing infection from SARS-CoV-2 infection. Meanwhile, the ROC curve demonstrated that PDW (AUC=0.786, the optimal cutoff at 15%) has a good ability to differentiate between infection and SARS-CoV-2 infection. This study demonstrates that routine blood parameters can be used as auxiliary diagnostic indicators for infection and provide reference for the diagnosis and differentiation of clinical infection.