The use of 8-diff clinical blood testing of patients to assess the severity of the new coronavirus infection

Introduction. A new coronavirus infection causes a variety of changes in the body of an infected person, which can be monitored using clinical blood analysis. The capabilities of flow cytometry allow to expanding the range of analyzed cell populations, which gives a more complete picture of the patient’s condition and the course of infection process.Aim. To study the extended 8-diff clinical blood analysis in patients with COVID-19 and to identify the parameters characterizing a severe course and an unfavorable outcome.Material and Methods. The study group comprised 282 patients with a confirmed diagnosis of a new coronavirus infection. The following parameters of the extended 8-diff clinical blood test were evaluated: the total content of leukocytes and their populations, the number of reactive and antibody-synthesizing lymphocytes (RE-LYMPH, AS-LYMPH), indicators characterizing the reactivity and granularity of neutrophils (NEUT-RI, NEUT-GI), erythrocyte count, hemoglobin level, normoblast count, and platelet count. Statistical data were processed using the Statistica 10.0 software.Results. The blood picture of patients with a severe course of COVID-19 as well as of those with an unfavorable outcome of disease was characterized by neutrophilia, normoblastemia, and an increase in the number of immature granulocytes. At the same time, there was a significant decrease in the number of lymphocytes and monocytes below the reference interval and a decrease in the number of eosinophils to the extent of complete absence. The performed logistic regression analysis allowed to determine the most significant hematological parameters in predicting the outcome of COVID-19 as follows: the total number of leukocytes (OR 1.3), neutrophils (OR 2.1), reactive neutrophils (OR 1.3), eosinophils (OR 0.05), monocytes (OR 0.2), lymphocytes (OR 0.4), and neutrophil-to-lymphocyte ratio (NLR) (OR 1.4). Also, the threshold values were established for these parameters as follows: the total number of leukocytes > 7.2 × 109/L, neutrophils > 5 × 109/L, reactive neutrophils > 48.6 Fi, eosinophils 2.9 were associated with an unfavorable outcome of the disease.Conclusion. The obtained data may be used for a comprehensive evaluation of COVID-19 patient condition along with other laboratory markers of the severe course of the infection.