JAK2 and Increased total eosinophil count: They are mainly classified as reactive, neoplastic/myeloproliferative and idiopathic eosinophilia[10]: eosinophilia is considered reactive if it is cytokine-driven, ranging from inflammatory diseases to parasitic infections; neoplastic/myeloproliferative eosinophilia is considered if clonal eosinophilia indicators such as PDGFRA and PCM-JAK2 rearrangement are detected; the diagnosis of idiopathic eosinophilia can only be made after the above 2 exclusions.