Table 2.

2016 WHO diagnostic criteria for polycythaemia vera (PV)

PV diagnosis requires meeting either all three major criteria or the first two major criteria and one minor criterion
Major criteria	Hb >165g/L (men)/>160g/L (women) or HCT >49% (men)/>48% (women) or increased red cell mass more than 25% above mean normal predicted value
	BM biopsy showing hypercellularity for age with trilineage growth including prominent erythroid, granulocytic and megakaryocytic proliferation with pleomorphic mature megakaryocytes (difference in size)
	Presence of JAK2 or JAK2 exon 12 mutation
Minor criteria	Subnormal serum erythropoietin level
	Criterion number 2 (BM biopsy) may not be required in cases with sustained absolute erythrocytosis: Hb levels 185g/L in men (HCT 55.5%) or 165g/L in women (HCT 49.5%) if major criterion 3 and the minor criterion are present. However, initial myelofibrosis (present in up to 20% of patients) can only be detected by performing a BM biopsy; this finding may predict a more rapid progression to overt myelofibrosis

BM, bone marrow; Hb, haemoglobin; HCT, haematocrit.