Table 1. Vis-a-vis comparison of the... | American Society of Hematology

Table 1.

Vis-a-vis comparison of the 2001 WHO diagnostic criteria for essential thrombocythemia (ET) and the 2007 expert panel proposal for revision.

Current WHO criteria²⁶	Proposals for revision¹⁰
* For details please refer to Vardiman et al²⁶ and Tefferi et al¹⁰.
Positive criteria Sustained platelet count ≥ 600 × 10⁹/L Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic lineage with increased number of enlarged, mature megakaryocytes   Exclusion criteria  No evidence of polycythemia vera* No evidence of chronic myelogenous leukemia* No evidence of chronic idiopathic myelofibrosis* No evidence of myelodysplastic syndromes No evidence that thrombocytosis is reactive due to: underlying inflammation or infection underlying neoplasm prior splenectomy	Sustained platelet count ≥ 450 × 10⁹/L Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic lineage with increased numbers of enlarged, mature megakaryocytes. No significant increase or left-shift of neutrophil granulopoiesis or erythropoiesis Not meeting the WHO criteria for polycythemia vera, primary myelofibrosis, chronic myelogenous leukemia, myelodysplastic syndrome, or other myeloid neoplasm* Demonstration of JAK2V617F or other clonal marker or, in the absence of a clonal marker, no evidence for reactive thrombocytosis  Diagnosis requires all four criteria are satisfied.

Current WHO criteria²⁶	Proposals for revision¹⁰
* For details please refer to Vardiman et al²⁶ and Tefferi et al¹⁰.
Positive criteria Sustained platelet count ≥ 600 × 10⁹/L Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic lineage with increased number of enlarged, mature megakaryocytes   Exclusion criteria  No evidence of polycythemia vera* No evidence of chronic myelogenous leukemia* No evidence of chronic idiopathic myelofibrosis* No evidence of myelodysplastic syndromes No evidence that thrombocytosis is reactive due to: underlying inflammation or infection underlying neoplasm prior splenectomy	Sustained platelet count ≥ 450 × 10⁹/L Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic lineage with increased numbers of enlarged, mature megakaryocytes. No significant increase or left-shift of neutrophil granulopoiesis or erythropoiesis Not meeting the WHO criteria for polycythemia vera, primary myelofibrosis, chronic myelogenous leukemia, myelodysplastic syndrome, or other myeloid neoplasm* Demonstration of JAK2V617F or other clonal marker or, in the absence of a clonal marker, no evidence for reactive thrombocytosis  Diagnosis requires all four criteria are satisfied.

Current WHO criteria²⁶

Proposals for revision¹⁰

* For details please refer to Vardiman et al²⁶ and Tefferi et al¹⁰.

Positive criteria

Sustained platelet count ≥ 600 × 10⁹/L
Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic lineage with increased number of enlarged, mature megakaryocytes

  Exclusion criteria 

No evidence of polycythemia vera*
No evidence of chronic myelogenous leukemia*
No evidence of chronic idiopathic myelofibrosis*
No evidence of myelodysplastic syndromes
No evidence that thrombocytosis is reactive due to:
- underlying inflammation or infection
- underlying neoplasm
- prior splenectomy

Sustained platelet count ≥ 450 × 10⁹/L
Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic lineage with increased numbers of enlarged, mature megakaryocytes. No significant increase or left-shift of neutrophil granulopoiesis or erythropoiesis
Not meeting the WHO criteria for polycythemia vera, primary myelofibrosis, chronic myelogenous leukemia, myelodysplastic syndrome, or other myeloid neoplasm*
Demonstration of JAK2V617F or other clonal marker or, in the absence of a clonal marker, no evidence for reactive thrombocytosis  Diagnosis requires all four criteria are satisfied.