* 90%-95% have the t(9;22)(q34;q11.2) there are rare cases of variant translocations or cryptic translocations; absolute basophilia is invariably present and eosinophilia is common. Small, hypolobated megakaryocytes (“dwarf megakaryocytes”) are usually present.
† In the absence of a clonal cytogenetic or molecular marker, rule out reactive neutrophilia and an underlying tumor.