Published: 2021-07-28

Changes in morphology of white blood cells on peripheral smear in COVID-19 infection

Garima Agarwal, Shubhangi Gupta, Natasha Singh, Salony Mittal, Atul Verma, Manjit S. Bindra, Gaurav Garg


Background: COVID-19 is an infectious disease caused by a newly discovered coronavirus, and has spread around the world in a deadly pandemic. The first case of COVID-19 was reported from Wuhan, China in December 2019. This is also called as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because of its homology with SARS virus. The most common hematological manifestation of coronavirus is lymphopenia which is due to depletion of lymphocytes by coronavirus infection. Other manifestations are neutrophilia and mild thrombocytopenia. Literature is full of quantitative hematological parameters but the researches on morphology of white blood cells is still ongoing. We at our institute done study on 60 confirmed positive cases of COVID-19, and analyzed those peripheral smears in terms of morphology of white blood cells.

Methods: The study was done using peripheral smear staining with methylene blue stain and was screened for various changes in white blood cells in peripheral smear.

Results: Changes in the white blood cells were examined in the peripheral smear and findings were made in the tabular form.

Conclusions: To conclude that all these changes are due to the virus infecting them or are secondary to pathogenesis of COVID disease, needs to be evaluated by larger studies.


COVID-19, Neutrophilia, Blebbing, Lymphopenia, Toxic granules, Vacuolation

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Tiwari N, Krishnan NR, Singh S, Madan J, Nath D, Tripathi S, et al. COVID 19 and pancytopenia: A single case experience of a pediatrics Institute. Saudi J Pathol Microbiol. 2020;5(5):308-10.

Thomas L. Does COVID-19 infect peripheral blood cells? Available at: https://www.newsmedical. net/news/20200519/Does-COVID-19-infect-peripheral- blood-cells.aspx. Accessed on 15 February 2021.

Mitra A, Dwyre DM, Schivo M, Thompson GR, Cohen SH, Ku N, Graff JP. Leukoerythroblastic reaction in a patient with COVID-19 infection. Am J Hematol. 2020;95(8):999-1000.

Zini G, Bellesi S, Ramundo F, d’Onofrio G. Morphological anomalies of circulating blood cells in COVID-19. Am J Hematol. 2020;95:870-2.

Singh A, Sood N, Narang V, Goyal A. Morphology of COVID-19–affected cells in peripheral blood film. BMJ Case Rep. 2020;13:e236117.

Singh S, Madan J, Nath D, Tiwari N. Peripheral Blood Smear Morphology- A Red Flag in COVID-19. Int J Trop Dis Health. 2020;41(8):54-8.

Imran MM, Ahmad U, Usman U, Ali M, Shaukat A, Gul N. Neutrophil/lymphocyte ratio-A marker of COVID-19 pneumonia severity. Int J Clin Path. 2021;75(4).

Vafadar Moradi E, Teimouri A, Rezaee R, Morovatdar N, Foroughian M, Layegh P, et al. Increased age, neutrophil-to-lymphocyte ratio (NLR) and white blood cells count are associated with higher COVID-19 mortality. Am J Emerg Med. 2021;40:11-4.

Bwire GM. Coronavirus: Why Men are More Vulnerable to Covid-19 Than Women? SN Compr Clin Med. 2020:1-3.

Terpos E, Ntanasis-Stathopoulos I, Elalamy I, Kastritis E, Sergentanis TN, Politou M, et al. Hematological findings and complications of COVID-19. Am J Hematol. 2020;95(7):834-47.

Nazarullah A, Liang C, Villarreal A, Higgins RA, Mais DD. Peripheral blood examination findings in SARSCoV- 2 infection. Am J Clin Pathol. 2020;154:319-29.

Pozdnyakova O, Connell NT, Battinelli EM, Connors JM, Fell G, Kim AS: Clinical significance of CBC and WBC morphology in the diagnosis and clinical course of COVID-19 infection. Am J Clin Pathol. 2021;155:364-75.

Zhang D, Guo R, Lei L. COVID19 infection induces readily detectable morphological and inflammation related phenotypic changes in peripheral blood monocytes. J Leukoc Biol. 2021;109:13-22.