Table 1.

Summary of the diagnostic criteria for CNL and aCML from the 2016 revision of the WHO criteria for myeloid neoplasms and acute leukemia

	CNL	aCML
Peripheral blood leukocytosis	WBCs ≥25 × 109/L, ≥80% segmented neutrophils and band, <10% neutrophil precursors, rare myeloblasts, monocytes <1 × 109/L	Neutrophils, promyelocytes, myelocytes, and metamyelocytes ≥10% of leukocytes, no or minimal basophilia and monocytosis, <20% blasts
Dysgranulopoiesis	No	Yes
Bone marrow hypercellularity	Yes; increased neutrophil granulocytes, normal neutrophil maturation, <5% of nucleated cells are myeloblasts	Yes; granulocytic proliferation and dysplasia are present, <20% blasts
Do not meet WHO criteria for other disorders	BCR-ABL1 + CML, PV, ET, PMF	BCR-ABL1 + CML, PV, ET, PMF
Exclusionary genetic criteria	No rearrangement of PDGFRA, PDGFRB, or FGFR1; no PCM1-JAK2	No rearrangement of PDGFRA, PDGFRB, or FGFR1; no PCM1-JAK2
Inclusionary genetic criteria	Presence of an activating CSF3R mutation, such as T618I*

ET, essential thrombocythemia; PMF, primary myelofibrosis; PV, polycythemia vera.

^*If no CSF3R mutation is present, the diagnostic criteria for CNL can still be met if there is persistent neutrophilia, splenomegaly, and no evidence of the neutrophilia being a reactive process.