Background: Abnormalities in blood counts were seen from the onset of the first cases of COVID-19, which were then studied in several studies, demonstrating the correlation between certain abnormality and the stage and severity of the disease
Aims: describe the current status of blood count alterations in patients with COVID-19 and to summarise the crucial role of specific haematological parameters during the disease and the prognosis
Methods: This is a monocentric retrospective study of 122 patients with SARS-Cov-2 infection, admitted according to the severity of the infection in the intensive care unit (severe forms) and isolation unit (moderate forms). The demographic and clinical informations were collected, the analysis of the blood counts was carried out by the SYSMEX cellular haematology machine and the cytological study of the blood smears using the LEICA
Results: Hyperleukocytosis was present in 70.5% of the patients mainly due to neutrophilia (75.4%), we've also found a lymphopenia (59.8%), thrombocytopenia (14.8%), and anemia (50.8%). Thus neutrophilia and lymphopenia were significantly higher in resuscitated and deceased patients than in isolation and recovered patients (p < 0.05). In addition, NLR levels > 6.5 were found in 94.3% of resuscitated patients and 88% of deceased patients and PLR levels > 123 were found in 86% of resuscitated patients and 86% of deceased patients. Finally, some morphological abnormalities of blood cells (neutrophils with toxic granulations, activated lymphocytes.....) have been described.
Conclusion(s): Our study demonstrated that certain abnormalities such as lymphopenia, neutrophilia, and thrombocytopenia are closely related to COVID-19 infection, thus demonstrating the role of the immunothrombosis phenomenon in the pathophysiology of SARS-Cov-2 infection. Our study has highlighted the importance of blood counts in COVID-19, which can help predict prognosis, assess severity, and monitor progress. The follow-up of the evolution of haematological data allows to improve the health of patients with COVID-19