Variations in complete blood counts and cellular morphological alterations in blood smear of COVID-19 patients from a tertiary care center

Corona viruses are a large family of viruses of which Corona virus disease 19 (COVID 19) infection evokes a hyperinflammatory response and severe acute respiratory distress syndrome in human beings. Complete blood count evaluation and peripheral smear examination is an essential tool for early diagnosis and management of COVID-19 positive patients. This study was aimed to evaluate the variations in complete blood counts (CBC) and changes in the cellular morphology in the blood smear in patients affected with COVID-19. This was an observational study, undertaken in a tertiary care center. The study included baseline blood samples from 96 proven COVID-19 positive cases. The samples were subjected for automated complete blood count analysis and peripheral smear examination. Thequantitative data were expressed by mean and Standard deviation. Qualitative categorical variables were expressed as numbers and percentages. Out of the total 96 cases, the most common quantitative finding was neutrophilic leukocytosis with relative lymphopenia. Five cases of absolute lymphopenia was observed. Majority of the cases had normal hemoglobin values and normal platelet counts. The characteristic morphological changes were seen in neutrophils and lymphocytes. The neutrophils showed presence of toxic granules, cytoplasmic vacuolations and hypolobation.The morphological alteration in lymphocytes included reactive lymphocytes with plasmacytoid and monocytoid morphology, large granular lymphocytes and Turk cells. Infrequent finding of leukoerythroblastic reaction was also observed in our study. To summarize, hematological investigation of COVID 19 cases may show several abnormal findings. Quantitative findings like Neutrophilia and lymphopenia were characteristic, whereas, the most common morphological alteration observed was atypical lymphocytes. Quantitative and qualitative alterations of hematological parameters are one of the investigations which would aid timely diagnosis of the disease. Toxic granules and cytoplasmic vacuolations in neutrophils may indicate ongoing sepsis in COVID 19 patients which in turn aids in efficient management of the patients to reduce the mortality rate.