Morphological Changes in Peripheral Blood in COVID-19 Infection.

Abstract

Background and Objectives: Quantitative, as well as qualitative changes in lymphocytes associated with viral infections, are a known fact. However, coronavirus seems to have trilineage involvement in hematopoietic cells. The study was conducted to assess the association of morphology changes in peripheral blood smear with the severity of the disease and to develop a risk scoring system for early detection of severity in COVID-19 patients.

Material and methods: This was an prospective observational study conducted at a tertiary care referral center in North India. A total of 92 patients diagnosed between 1st to 31st March 2021 with COVID-19 infection by RT-PCR testing were included in the study. Multivariate binary logistic regression analysis was used to assess the independent predictors whereas the ROC curve was used to assess the diagnostic accuracy and a corresponding cut-off value of the risk scoring system.

Result: Out of the total, 40/92(43.4%) patients were having severe disease. White blood cells (WBC) and neutrophil morphology were identified as significant independent risk factors for severity and included in the risk scoring system. Risk scores ranged from 0-9, a higher score indicates higher severity. Total 12% of patients had scores 0 whereas 12% had scores in the range of 6-9. Area under ROC (AUROC) curve indicates that accuracy of the severity risk score was 80.8% with at-risk score ≥3 and ≥4, sensitivity/specificity were 80%/65.4% and 77.5%/73.1% respectively with a good agreement (75%, p>0.05) between predicted and observed severity.

Conclusion: White blood cells and Neutrophil morphology are significant independent risk factors for disease severity. Complete blood count along with peripheral blood smear examination for morphological changes and its scoring system is a quick, simple, and cheap method which can be useful not only to predict severity but also in daily monitoring daily in COVID-19 infection especially which is more useful in a setting of limited resources. However, studies with more patients are needed to validate the results.