Complete Blood Count as an Indicator of COVID-19 Disease Severity

Background: SARS-CoV-2 virus caused the COVID-19 pandemic worldwide. One of the main pathogenic features of this virus is unpredictable clinical sequence rapidly progressing to lethal complications. Identification of clinical and laboratory prognostic factors for severe COVID-19 may contribute to the management of follow-up and treatment modalities of the disease. Complete blood count (CBC) is a fast and inexpensive laboratory test which provides a wealth of information on individual health status. Objectives: This study aimed to evaluate the CBC test parameters in COVID-19 patients compared to healthy individuals. Methods: We performed a retrospective study on 147 patients with COVID-19 and 95 healthy subjects as the control group. Based on the severity of COVID-19, the patients were divided into 4 groups including mild, moderate, severe and deceased. Complete blood count parameters were recorded in all groups and obtained data were analyzed using the chi-square test at the significance level of P < 0.05 (SPSS, version 23). Results: The severity of the disease increased with age and men were more likely to die from disease complications. Most CBC parameters were found to be significantly increased in patients. Significantly increased neutrophils and decreased lymphocytes were the most relevant predictors of severe disease and death. The only CBC parameter that was not associated with the disease was basophil count. Conclusions: The CBC, especially in terms of the neutrophil and lymphocyte parameters is a simple and accurate test that can be used to predict the severity of the COVID-19 disease.