2001 World Health Organization criteria for essential thrombocythemia
| 2001 criteria for ET . |
|---|
| Positive criteria |
| 1. Sustained platelet count ≥ 600 × 109/L |
| 2. Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic lineage with increased numbers of enlarged, mature megakaryocytes |
| Criteria of exclusion |
| 1. No evidence of polycythemia vera |
| a. Normal red cell mass or hemoglobin < 18.5 g/dL in men, 16.5 g/dL in women |
| b. Stainable iron in marrow, normal serum ferritin, or normal MCV |
| c. If the former condition is not met, failure of iron trial to increase red cell mass or hemoglobin levels to the PV range |
| 2. No evidence of chronic myeloid leukemia: no Philadelphia chromosome and no BCR-ABL fusion gene |
| 3. No evidence of chronic idiopathic myelofibrosis |
| a. Collagen fibrosis absent |
| b. Reticulin fibrosis minimal or absent |
| 4. No evidence of myelodysplastic syndrome |
| a. No del(5q), t(3;3)(q21;q26), inv(3)(q21q26) |
| b. No significant granulocytic dysplasia, few, if any, micromegakaryocytes |
| 5. No evidence that thrombocytosis is reactive caused by |
| a. Underlying inflammation or infection |
| b. Underlying neoplasm |
| c. Prior splenectomy |
| 2001 criteria for ET . |
|---|
| Positive criteria |
| 1. Sustained platelet count ≥ 600 × 109/L |
| 2. Bone marrow biopsy specimen showing proliferation mainly of the megakaryocytic lineage with increased numbers of enlarged, mature megakaryocytes |
| Criteria of exclusion |
| 1. No evidence of polycythemia vera |
| a. Normal red cell mass or hemoglobin < 18.5 g/dL in men, 16.5 g/dL in women |
| b. Stainable iron in marrow, normal serum ferritin, or normal MCV |
| c. If the former condition is not met, failure of iron trial to increase red cell mass or hemoglobin levels to the PV range |
| 2. No evidence of chronic myeloid leukemia: no Philadelphia chromosome and no BCR-ABL fusion gene |
| 3. No evidence of chronic idiopathic myelofibrosis |
| a. Collagen fibrosis absent |
| b. Reticulin fibrosis minimal or absent |
| 4. No evidence of myelodysplastic syndrome |
| a. No del(5q), t(3;3)(q21;q26), inv(3)(q21q26) |
| b. No significant granulocytic dysplasia, few, if any, micromegakaryocytes |
| 5. No evidence that thrombocytosis is reactive caused by |
| a. Underlying inflammation or infection |
| b. Underlying neoplasm |
| c. Prior splenectomy |