"absence of BCR-ABL1-positive chronic myeloid leukaemia, polycythaemia vera, primary myelofibrosis, or other myeloloid neoplasm"
"JACK2 V617F, CALR, or MPL mutation"
"The disease has traditionally been a diagnosis of exclusion, requiring the absence of reactive conditions and other clonal disorders that may present with thrombocytosis. The discovery of mutations in JAK2 and MPL now allows for the positive identification of essential thrombocythaemia in more than one-half of all cases."