Materials and methods
We investigated files of those patients admitted to Bursa City Hospital/Bursa/Turkey between March-August 2020 with complaints compatible with COVID-19. In a total 10000 patients retrospectively evaluated. Out of 10000 patients those who were found to be positive for Covid-19 and were completely healthy before the disease were included in the study. In a total 318 Covid-19 patients who met the specified criteria and 156 healthy controls those tested negatively and had no chronic diseases included. We divided Covid-19 patients into two groups, the main group consisted of those patients who had penumonia on computed tomography of the lungs, the second gruop consisted of those patients tested positively with PCR but had no penumonia on computed tomography of the chest. And the third group consisted of healthy subjects. The demographic and clinical data of all patients is shown on table 1. The three patient groups were compared by examining the hemogram parameters (WBC, neutrophil, lymphocyte, monocyte, eosinophil, platelets, PDW, MPV and RDW) obtained at the time of hospital admission before using any kind of medication. NLR, PLR and MLR values were calculated by dividing neutrophil, platelet and monocyte levels to lymphocyte count. Patients with chronic diseases, those using a medication and pregnants were exluded. After obtaining scientific research approval for the study from the Ministry of Health General Directorate of Health Services, the ethics committee approval was obtained from Bursa City Hospital Clinical Research Ethics Committee (Ethics Committee Approval No:2021-2/2). All the statistical analyses were carried out using SPSS 25.0 software. A Kolmogorov-Smirnov test was performed for the normality of the sample data, and the continuous variables were defined by the mean ± standard deviation, median (interquartile range %25–%75), while the categorical variables were expressed as frequency and percent. In order to compare the independent groups, One-way ANOVA Bonferroni for the parametric test assumptions, and a MannWhitney U test for non-parametric assumptions were used. The Roc analysis was performed for optimal cut-off values to predict SARS-CoV-2 positivity. We exploited Youden Index values to identify the optimal cut-off values. In addition, p value less than 0.05 was set as the statistical significance level.