Abstract

Introduction: COVID-19 is a highly contagious and deadly disease. However, there is no accurate diagnostic test to predict its severity. The aim of this study was to determine the relationship between the lymphocyte counts and CRP levels and the severity of pulmonary involvement shown in the CT scan of the patients with pneumonia caused by COVID-19.

Methods: In this cross-sectional study, demographic information and laboratory findings of the patients with COVID-19 were collected. Then, each patient's pulmonary involvement was scored based on the CT scan results. The data were analyzed using SPSS 16 software as well as ANOVA, chi-square test, Pearson correlation coefficient, and ROC curve.

Results: Data of 125 COVID-19 patients with the mean age of 59.37 ± 1.5 showed that the prevalence of lymphocytes < 1100 × 10⁹/L and CRP > 100 mg/L was higher in the patients with severe pulmonary involvement than in those with mild involvement (p < 0.001). Furthermore, an increase in pulmonary involvement severity observed in HRCT led to decreased absolute blood lymphocyte count and increased CRP levels (p < 0.001). The CRP test with an area under the ROC curve of 0.76 could be an acceptable test for predicting the severity of pulmonary involvement in patients with pneumonia caused by COVID-19.

Conclusion: It was found out in this study that there was a significant positive correlation between CRP levels and the severity of COVID-19 pneumonia. The CRP test could also be an acceptable test for predicting the severity of pulmonary involvement in COVID-19.