Diagnosis of JAK2 positive myelofibrosis requires both of the following:
(1) presence of both A1 and A2
(2) 2 or more of B criteria
Diagnosis of JAK2 positive myelofibrosis requires both of the following:
(1) presence A1, A2 and A3
(2) 2 or more of B criteria
Criteria for JAK2 positive polycythemia: A1 and A2
(1) presence of JAK2 mutation
(2) increased bone marrow reticulin (Grade 3 or 4 on a scale of 0 to 4)
Criteria for JAK2 negative polycythemia: A1 to A3
(1) absence of JAK2 mutation
(2) increased bone marrow reticulin (Grade 3 or 4 on a scale of 0 to 4)
(3) absence of BCR-ABL fusion gene
Criteria for myelofibrosis: B1 through B6
(1) palpable splenomegaly
(2) otherwise unexplained anemia (hemoglobin for male < 11.5 g/dL; for female < 10 g/dL)
(3) teardrop shaped red blood cells seen in the peripheral blood smear
(4) leukoerythroblastic peripheral blood smear (presence of nucleated red blood cells and immature myeloid cells)
(5) systemic symptoms (diffuse bone pain; drenching night sweats; unintended weight loss > 10% over 6 months)
(6) histologic evidence of extramedullary hematopoiesis
