Overview of Bone Marrow Diagnosis in Leukemia, July 30, 1998

Overview of Bone Marrow Diagnosis in Leukemia, July 30, 1998

Acute leukemia: There is a marked or extreme increase in nucleated cells (this is referred to as active bone marrow proliferation). A characteristic feature is that blast cells account for more than 30% of the total cell count. When granulocytes predominate, it is called acute granulocytic leukemia. Among acute granulocytic leukemias, those with blasts exceeding 90% are classified as M1; those with promyelocytes accounting for more than 30% are M2; M3 refers to cases with more than 30% early myelocytes; M4 denotes cases with more than 30% promonocytes and early myelocytes; M5 indicates more than 30% monoblasts; M6 means more than 30% erythroid lineage with more than 30% proerythroblasts; and M7 signifies more than 30% megakaryoblasts. Acute lymphocytic leukemia: Prolymphocytes account for more than 30%–20%; L1 represents small cells, L2 large cells (inconsistent), and L3 large cells (consistent). Chronic leukemia: In the bone marrow, immature cells are mainly metamyelocytes and late myelocytes, with blast cells not exceeding 10%. Indicators of chronic-to-acute transformation: if blast cells exceed 6%, it is considered suspicious; 10%–30% indicates an aggressive phase; and 30% marks the transition to acute leukemia. Complete remission: Blast cells are less than 5%.