WHO diagnostic criteria for primary myelofibrosis

Last reviewed 05/2021

The following criteria have been proposed by the WHO for the diagnosis of primary myelofibrosis.

• major criteria - requires meeting all 3 major criteria
  • megakaryocyte proliferation and atypia accompanied by either reticulin and/or collagen fibrosis, or In the absence of reticulin fibrosis, the megakaryocyte changes must be accompanied by increased bone marrow cellularity, granulocytic proliferation and often decreased erythropoiesis (ie, prefibrotic PMF)
  • not meeting WHO criteria for CML, PV, MDS, or other myeloid neoplasm
  • demonstration of JAK2V617F or other clonal marker or no evidence of reactive bone marrow fibrosis
    
    
• minor citeria - requires meeting 2 minor criteria
  • leukoerythroblastosis
  • increased serum LDH
  • anemia
  • palpable splenomegaly

Reference:

• 1. Tefferi A, Thiele J, Vardiman JW. The 2008 World Health Organization classification system for myeloproliferative neoplasms: order out of chaos. Cancer. 2009;115(17):3842-7.