The diagnostic value of neutrophil to lymphocyte ratio in determining the severity of COVID-19

Background: Changes in hematological parameters play a role in the pathogenesis of coronavirus disease 2019 (COVID-19). We aimed to investigate the significance of neutrophil-lymphocyte ratio (NLR) and hematologic parameters in determining the severity of COVID-19. Methods: This retrospective cross-sectional study was conducted on adult patients diagnosed with COVID-19 in two pandemic hospitals between 01, April, and 01, July 2020. Using the COVID-19 diagnostic criteria of the world health organization (WHO), the patients were divided into two groups as severe and non-severe. Demographic and clinical characteristics, white blood cell (WBC), neutrophil, lymphocyte and platelet counts, and NLR of all patients were examined at the first admission. Multivariate analyzes were performed to determine the independent predictive data and ROC analysis to test the diagnostic accuracy of the hematological parameters. Results: Of the 381 patients included in the study, 42 (11%) had severe COVID-19 infection. While the mean NLR was 7.61±7.48 in patients with severe COVID-19, the mean NLR of non-severe patients was 2.97±2.37 (95% CI: 2.294 to 6.984, p