Background: The aim is to explore the value and significance of changes in neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) in the diagnosis and treatment of patients with influenza virus infection.
Methods: A total of 1,330 cases of influenza A diagnosed with the nucleic acid testing were collected according to the 2019 version of the influenza diagnosis and treatment regimen in our hospital from September 2020 to December 2020. During the same period, 1,330 cases of healthy subjects were used as controls. The colloidal gold method and fluorescent PCR were used to detect influenza A virus. The sysmex800i was used for routine blood test, and statistical analysis was then performed.
Results: Comparing the relevant indicators between the research group and the healthy control group showed that the differences in NLR, PLR, PLT, absolute lymphocyte values, etc. were all statistically significant (p < 0.001). Among them, the average results of NLR and PLR of the research group were all larger than those of the control group; the mean values of the absolute value of lymphocytes (x 109) and PLT (x 109) in the research group were all smaller than those of the control group. The NLR, PLR, LMR, age, and other parameters of the research group and the healthy control group were analyzed to determine whether there was influenza infection according to a binary logistic regression model. The results showed that the differences were not statistically significant except for age and LMR (p > 0.05) and did not enter the regression model. The differences in other parameters such as NLR and PLR were all statistically significant (all p < 0.001), which were all entered into the regression model. They were very significant for predictive diagnosis of influenza A. The areas under the ROC curve of NLR and PLR were 0.961 (95% CI: 0.953-0.968) and 0.749 (95% CI: 0.730-0.769), respectively; the sensitivity and specificity of NLR were 88.4% and 93.1%, respectively, and Youden’s index was 0.815, the optimal diagnostic cutoff value was 1.478; the sensitivity and specificity of PLR were 56.70% and 89.60%, respectively; the Youden’s index was 0.463, and the optimal diagnostic cutoff value was 124.
Conclusions: NLR and PLR had a certain degree of accuracy in the diagnosis of viral infections in children with influenza A. The diagnostic effect of NLR was particularly good. In the early stage of the disease, cheap and easily available blood biomarkers can be used to diagnose influenza A. However, LMR had no diagnostic value for influenza A because the area under the curve was too small.