Table 1.

Definition of chronic, accelerated and blastic phases of chronic myeloid leukemia by World Health Organization Criteria

CML phase definition
Chronic phase
Presence in peripheral blood or bone marrow of blasts <10%, basophils <20%, blasts and promyelocytes <30%, and platelets ≥100 × 109/L
Accelerated phase
Peripheral blood or bone marrow blasts of 10%–19%, or blasts and promyelocytes ≥30%, or basophils ≥20%, or platelets <100 × 109/L not related to therapy, or chromosomal abnormalities other than the Ph chromosome, or progressive splenomegaly
Blast crisis
Presence of >20% blasts in blood or bone marrow or evidence of extramedullary blast infiltration (except liver, spleen, or lymph nodes) or large clusters of blasts in bone marrow biopsy