Criteria for essential thrombocythemia - both of the following:
(1) sustained platelet count >= 600,000 per µL
(2) megakaryocytic hyperplasia in a bone marrow biopsy with increased numbers of mature megakaryocytes
where:
• There should be no or few micromegakaryocytes (as seen in myelodysplasia)
Exclusions - none of the following:
(1) polycythemia vera, including mixed with iron deficiency
(2) chronic myeloid leukemia
(3) Philadelphia chromosome
(4) BCR-able fusion gene
(5) chronic idiopathic myelofibrosis
(6) myelodysplasia
(7) cytogenetic abnormalities associatd with myelodysplasia:
(7a) del(5q)
(7b) t(3;3)(q21:q26)
(7c) inv(3)(q21:q26)
(8) reactive thrombocytosis due to cancer, infection, inflammation or after splenectomy
