WHO criteria for ET
| WHO ET criteria . |
|---|
| Major criteria |
| 1. Platelet count ≥450 × 109/L |
| 2. BM biopsy showing proliferation mainly of the megakaryocyte lineage with increased numbers of enlarged, mature megakaryocytes with hyperlobulated nuclei. No significant increase or left shift in neutrophil granulopoiesis or erythropoiesis and very rarely minor (grade 1) increase in reticulin fibers |
| 3. Not meeting WHO criteria for BCR-ABL1+ CML, PV, PMF, myelodysplastic syndromes, or other myeloid neoplasms |
| 4. Presence of JAK2, CALR, or MPL mutation |
| Minor criterion |
| Presence of a clonal marker or absence of evidence for reactive thrombocytosis |
| Diagnosis of ET requires meeting all 4 major criteria or the first 3 major criteria and the minor criterion |
| WHO ET criteria . |
|---|
| Major criteria |
| 1. Platelet count ≥450 × 109/L |
| 2. BM biopsy showing proliferation mainly of the megakaryocyte lineage with increased numbers of enlarged, mature megakaryocytes with hyperlobulated nuclei. No significant increase or left shift in neutrophil granulopoiesis or erythropoiesis and very rarely minor (grade 1) increase in reticulin fibers |
| 3. Not meeting WHO criteria for BCR-ABL1+ CML, PV, PMF, myelodysplastic syndromes, or other myeloid neoplasms |
| 4. Presence of JAK2, CALR, or MPL mutation |
| Minor criterion |
| Presence of a clonal marker or absence of evidence for reactive thrombocytosis |
| Diagnosis of ET requires meeting all 4 major criteria or the first 3 major criteria and the minor criterion |