Abstract: Objective To explore the assessment value of neutrophil-to-lymphocyte ratio （NLR） for prognosis in coronavirus disease 2019 （COVID-19）. Methods Using the retrospective study，399 cases of COVID-19 admitted to Wuhan Fourth Hospital were selected as the research subjects. According to the clinical prognosis，they were divided into the survival group （n = 375） and the death group （n = 24）. The neutrophil count and lymphocyte count of patients on the first day of admission were collected to calculate the NLR，and the differences between neutrophils，lymphocytes and NLR in different groups were compared. The receiver-operating characteristic（ROC） curve was used to evaluate the optimal threshold of NLR for predicting prognosis. Results The neutrophils and NLR of the death group were significantly higher than that of the survival group， and the lymphocytes of the death group were significantly lower than that of the survival group. According to ROC curve analysis， the areas under the ROC curve of neutrophils，lymphocytes and NLR were 0. 759， 0. 838 and 0. 856， respectively， and the optimal thresholds were 4. 955 × 10⁹/L，0. 775 × 10⁹/L，and 6. 919，respectively. Conclusion NLR can be used as a simple and effective auxiliary indicator for prognostic evaluation of COVID-19 patients.

Key words: coronavirus disease 2019 （COVID-19）, novel coronavirus pneumonia, neutrophil-to-lymphocyte ratio, prognosis