CSF3R and chronic neutrophilic leukemia: Compared to previous diagnostic criteria for CNL, the 2016 diagnostic criteria emphasize (2) the presence of CSF3R T618I or other activating CSF3R mutation; if there is no CSF3R mutation, the criteria specify persistent neutrophilia (≥ 3 months), splenomegaly, and no other identifiable cause of reactive neutrophilia, including absence of PCD, or if present, demonstration of clonality of myeloid cells by cytogenetic or molecular studies.