Table 4.

Diagnostic criteria for polycythemia vera (PV) and post polycythemia vera myelofibrosis (post-PV MF) according to the International Consensus Classification¹

	PV		Post-PV MF
Major criteria	1. Elevated hemoglobin concentration or elevated hematocrit or increased red blood cell massa	Required criteria	1. Previous established diagnosis of PV
	2. Bone marrow biopsy showing age-adjusted hypercellularity with trilineage proliferation (panmyelosis), including prominent erythroid, granulocytic, and increase in pleomorphic, mature megakaryocytes without atypiab		2. Bone marrow fibrosis of grade 2 or 3
	3. Presence of JAK2V617F or JAK2 exon 12 mutationc
Minor criterion	Subnormal serum erythropoietin level	Additional criteria	1. Anemia (i.e., below the reference range given age, sex, and altitude considerations) or sustained loss of requirement of either phlebotomy (in the absence of cytoreductive therapy) or cytoreductive treatment for erythrocytosis
			2. Leukoerythroblastosis
			3. Increase in palpable splenomegaly of > 5 cm from baseline or the development of a newly palpable splenomegaly
			4. Lactate dehydrogenase level above the reference range

The diagnosis of PV requires all 3 major criteria or the first two major criteria plus the minor criterion. The diagnosis of post-PV MF is established by all two required criteria and at least two additional criteria

^aDiagnostic thresholds: hemoglobin: > 16.5 g/dL in men and > 16.0 g/dL in women; hematocrit: > 49% in men and > 48% in women; red blood cell mass: > 25% above mean normal predicted value

^bA bone marrow biopsy may not be required in patients with sustained absolute erythrocytosis (hemoglobin concentrations of > 18.5 g/dL in men or > 16.5 g/dL in women and hematocrit values of > 55.5% in men or > 49.5% in women) and the presence of a JAK2 V617F or JAK2 exon 12 mutation

^cIt is recommended to use highly sensitive assays for JAK2 V617F (sensitivity level < 1%)—in negative cases, consider searching for non-canonical or atypical JAK2 mutations in exons 12–15