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. This evidence concerns the gene CSF3R and Splenomegaly.