Haematological changes in sailors who had COVID-19.

The most typical laboratory change in WBC count in patients with the past COVID-19 is relative or absolute leukopenia. Persistent changes in WBC count are not always outside of the reference range for absolute values and should be assessed by a complex of typical changes. The presence of typical changes in WBC count in a patient with the past COVID-19 requires a profound examination for the post-COVID-19 syndrome.