Lymphocyte count as a predictor of severity of COVID-19 infection

Abstract

Background: Recent researches suggest that hematological profiles vary during SARS-CoV-2 infection. Patients with COVID-19 have a lower peripheral blood lymphocyte count in the early stages of the disease. Aim of study: To evaluate if level of lymphocyte at admission can be used as a predictor for severity and mortality of COVID-19 infection. Methods: A prospective observational study that was conducted at the COVID-19 ward in Al-Khidhir General Hospital during a period of one year. It included 350 patients who diagnosed with COVID-19 infection and admitted in the isolation wards. Complete blood count including WBC, hemoglobin, platelet count, lymphocyte count, neutrophil count, and monocyte count were assessed. Severity of disease was categorized into mild, moderate, severe, and critical. Results: In this study, patients with severe infection had significant lower means of lymphocyte count (0.84 versus 1.73 *109/µl, P= 0.001). The cut point of N/L ratio was 1.0 *109/µl. Hence, lymphocyte count < 1.0 109/µl is predictive for severe or critical stage of COVID-19. Conclusion: Hematological indices are easy and cheap way of assessing clinical progress in COVID-19 infection. One of the parameter is the lymphocyte count which show in our study significant correlation between the clinical stage. Lower count means progress to sever form of COVID-19.