The following revised diagnostic criteria for<unk>  were proposed in 2005. The diagnosis requires the presence of both A criteria together with B3 to B6, or of criterion A1 together with B1 to B6. The criteria are as follows: * A1. Platelet count > 400 × 103/µL for at least 2 months. * A2. Acquired V617F JAK2 mutation present * B1. No cause for a reactive thrombocytosis * normal inflammatory indices * B2. No evidence of iron deficiency * stainable iron in the bone marrow or normal red cell mean corpuscular volume * B3. No evidence of polycythemia vera * hematocrit < midpoint of normal range or normal red cell mass in presence of normal iron stores * B4. No evidence of chronic myeloid leukemia * But the Philadelphia chromosome may be present in up to 10% of cases. Patients with the Philadelphia chromosome have a potential for the development of acute leukemia, especially acute lymphocytic leukemia. * B5. No evidence of myelofibrosis * no collagen fibrosis and ≤ grade 2 reticulin fibrosis (using 0–4 scale) * B6. No evidence of a myelodysplastic syndrome * no significant dysplasia * no cytogenetic abnormalities suggestive of myelodysplasia
Essential thrombocythemia
Refractory cytopenia of childhood
Polycythemia vera
Transient erythroblastopenia of childhood
Primary myelofibrosis
Chronic neutrophilic leukemia
Drug-induced thrombocytopenic purpura
Aplastic anemia