Blood cell morphology and COVID-19 clinical course, severity, and outcome

COVID-19 infection affects different organs of the human body, and blood cells are not an exception. Peripheral blood smear (PBS) is a simple and available method to investigate blood cells’ morphologic changes. In this study, we aimed to determine the morphologic changes and abnormalities of COVID-19 patients and their relation to the patients’ clinical course. In this prospective cross-sectional study, we included 89 PCR-positive COVID-19 patients. A pathologist examined the PBS findings of these patients. The patients’ clinical course, including severity, outcome, intubation, and ICU admission, was extracted from their profiles. The statistical analyses were done to find out the relation between PBS findings and patients’ clinical course. Results showed that smudge cells are the most frequent abnormality in our participants. Other findings were schistocyte; atypical lymphocytes; and increased large granular lymphocytes, shift to left of granulocytes, giant platelets, and leukoerythroblastic reaction. Our results did not show any statistically significant relationship between PBS findings and their clinical course. Although other studies suggested PBS as a possible predictive tool for COVID-19 disease, our study showed that these findings could not predict nor relate to the patients’ clinical course.