The Importance of Neutrophil/Lymphocyte and Lymphocyte/Monocyte Ratios in The Diagnosis of Influenza in Children

Background: We aimed to analyze the neutrophil/lymphocyte ratio (NLR) and lymphocyte/monocyte ratio (LMR) to investigate their value in supporting the diagnosis of influenza in cases with influenza-like symptoms. Methods: A total of 5,693 pediatric patients who applied to the Pediatric Clinic between January 2015 and December 2018 were included in the study. Complete blood count and influenza rapid antigen tests were evaluated at the time of admission. Results: The mean LMR was significantly lower in patients with influenza A than non-influenza A patients (p < 0.001). LMR was also significantly lower in those with influenza A or B compared to those in the influenza-negative group (p < 0.001). There was no significant difference (p = 0.83) in terms of the mean LMR between influenza B positive and negative patients. The mean NLR was significantly higher in influenza A positive patients in comparison with influenza A negative patients (p < 0.001), and it was significantly lower in influenza B positive patients than in influenza B negative patients (p < 0.001). Conclusions: We concluded that LMR and NLR, which had been rarely examined in the literature, had important value in the diagnosis of influenza. However, these values alone were far from being sufficient for the definitive diagnosis of influenza.