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. The gene discussed is PDGFRB; the disease is Increased total eosinophil count.