Table 1.
Major criteria |
1. Hemoglobin >16.5 g/dL in men and >16 g/dL in women or, Hematocrit >49% in men and >48% in women or, red cell mass (RCM) >25% above mean normal predicted value |
2. Bone marrow biopsy showing hypercellularity for age with trilineage growth (panmyelosis) including prominent erythroid, granulocytic, and megakaryocytic proliferation with pleiomorphic, mature megakaryocytes (differences in size) |
3. Presence of a JAK2V617F or JAK2 exon 12 mutation |
Minor criterion |
Subnormal erythropoietin level |
Diagnosis requires meeting all three major criteria, or the first two major criteria and the minor criterion. Bone marrow biopsy may not be required in cases with sustained absolute erythrocytosis (hemoglobin levels >18.5 g/dL in men (hematocrit >55.5%) and >16.5 g/dL in women (hematocrit >49.5%) if major criterion 3 and the minor criterion are present.