Refractory anemia with excess blasts (RAEB), type 1 is a severe type of RAEB (see this term) characterized by cytopenias and the following hematological parameters: uni- or multilineage dysplasia, 5% to 9% blasts in bone marrow or 2% to 4% in peripheral blood, and no Auer rods (abnormal, needle-shaped or round inclusions in the cytoplasm of myeloblasts and promyelocytes). Median survival has been reported to be 18 months.