Abstract
Thrombocytopenia and absolute neutropenia are recognized manifestations of Epstein-Barr virus infectious mononucleosis (EBV-IM). This study conducted a retrospective analysis of laboratory results from patients clinically suspected of having EBV-IM and tested over a two-year period (2018-2019) at a single testing center in Ireland, aiming to determine the prevalence of these hematological complications. A cohort of 51 confirmed acute EBV-IM cases was established, and the incidence of thrombocytopenia and absolute neutropenia within this group was assessed. These findings were then compared to the frequencies observed in non-acute EBV-IM patients, both with and without atypical lymphocytes. Among the 51 patients diagnosed with acute EBV-IM, 14% presented with thrombocytopenia and absolute neutropenia, including instances of severe cases. A comparable prevalence of these conditions was noted in non-acute EBV-IM patients with identifiable atypical lymphocytes; however, a significantly lower incidence was found in non-acute EBV-IM patients lacking atypical lymphocytes. These results suggest that thrombocytopenia and absolute neutropenia occur in patients with viral infections and are not exclusive to acute EBV-IM.