Leukemoid Reaction in a Severe COVID-19 Patient.

Leukemoid reaction is defined by a leukocyte level above 50 x 103/µL with a predominance of mature neutrophils and the presence of immature granulocytic forms in the peripheral blood (left shift). We report a case of a 36-year-old woman with severe coronavirus disease 2019 (COVID-19) infection admitted to the ICU with a leukocytosis of 70.9 x 103/µL white blood cells (WBC) throughout her hospitalization. A left shift with bandemia along with toxic granulations was also noticed and further investigation excluded more commonly known causes. A presumptive diagnosis of leukemoid reaction was made secondary to COVID-19 infection; however, it could not be confirmed since workup for lymphoproliferative disorders could not be performed as the patient passed away. The leukemoid reaction could be associated with severe COVID-19 infection; however, more data are needed to evaluate this association.