COVID-19 Infection and Haematological Involvement: a Review of Epidemiology, Pathophysiology and Prognosis of Full Blood Count Findings

The unfolding COVID-19 pandemic began in December 2019 in Wuhan, Hubei Province. COVID-19 is a systemic infection affecting several systems including the haematopoietic system. Surveys illustrating the laboratory findings of these patients conclude that lymphocytopenia, neutrophilia and thrombocytopenia are prominent amongst them. Moreover, it has been reported a significant decrease in T lymphocyte subsets and an increase of inflammatory cytokines of hospitalized patients with COVID-19. Generally, thrombocytopenia is commonplace in critically ill patients and usually suggests serious organ malfunction. In view of this, this review investigates the correlation between these abnormalities and the prognosis and disease course. Full blood count is an easy, economic and widely available tool which may help to discriminate between patients with or without severe disease. Last but not least, this review examines potential pathophysiological mechanisms by the novel coronavirus which contribute to these haematological alterations aiding the clinicians to better understand this disease and provide more clinical treatment options.