Acute Myelogenous Leukemia

(FAB Classification)

Flowchart showing the FAB classifications of acute myelogenous leukemia

Lymphocytic leukemias can be subdivided by type of cell surface antigens: 95% are B-cell and 5% are T-cell type.

Classification Description
M0 Undifferentiated leukemia (98013) stem cells predominate or cell type unidentified
M1 Myeloblastic leukemia without maturation (98723—acute) immature white blood cells predominate
M2 Myeloblastic leukemia with maturation (98723—acute) with partial differentiation
M3 Promyelocytic leukemia (98663—acute) promyelocytes predominate

M4 Combination myeloblastic-monoblastic leukemia (98723—acute; 98683—chronic) each component constitutes greater than 20% of the blasts in the bone marrow

  • M4 acute myelomonocytic leukemia
  • M4E0 acute myelomonocytic leukemia with eosinophilia
M5 Monoblastic leukemia (98603—monocytic, NOS; 98913—acute; 98603—subacute; 98603—chronic; 98603 aleukemic) monoblasts predominate

  • M5a acute monocytic leukemia without differentiation (98913—monoblastic)
  • M5b acute monocytic leukemia with differentiation (promonocytic)
M6 Erythroleukemia (98403) immature red and white cells predominate
M7 Megakayrocytic leukemia (99103—acute)