Diagnostic criteria for ET (WHO vs PVSG)
| Criteria . | |
|---|---|
| WHO-ET16 | PVSG-ET14 |
| Sustained platelet count > 450 × 109/l | Platelet count > 600 × 109/l |
| Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic mass lineage with increased numbers of enlarged mature megakaryocytes | Hematocrit < 40% or normal RBC |
| No sign of increase or left shift of neutrophil granulopoiesis or erythropoiesis | No myelodysplastic syndrome |
| Not meeting WHO criteria for PV; PMF, CML, MDS, or other myeloid neoplasms | No Philadelphia chromosome |
| Demonstration of JAK2V617F or other clonal marker, or in absence of clonal marker | No reactive cause |
| No evidence of reactive thrombocytosis | Collagen fibrosis absent or < one-third biopsy area without marked splenomegaly and leukoerythroblastic reaction |
| Criteria . | |
|---|---|
| WHO-ET16 | PVSG-ET14 |
| Sustained platelet count > 450 × 109/l | Platelet count > 600 × 109/l |
| Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic mass lineage with increased numbers of enlarged mature megakaryocytes | Hematocrit < 40% or normal RBC |
| No sign of increase or left shift of neutrophil granulopoiesis or erythropoiesis | No myelodysplastic syndrome |
| Not meeting WHO criteria for PV; PMF, CML, MDS, or other myeloid neoplasms | No Philadelphia chromosome |
| Demonstration of JAK2V617F or other clonal marker, or in absence of clonal marker | No reactive cause |
| No evidence of reactive thrombocytosis | Collagen fibrosis absent or < one-third biopsy area without marked splenomegaly and leukoerythroblastic reaction |
CML, chronic myeloid leukemia; MDS, myelodysplastic syndrome.