If these translocations are negative, there is peripheral eosinophilia, or there is a history of leukocytosis with eosinophilia, we recommend FISH for ETV6-ABL1, FIP1L1-PDGFRA, PDGFRB, or FGFR1 rearrangements. Here, FGFR1 is linked to Increased total eosinophil count.