Anemia resulting from bone marrow failure (aplastic or hypoplastic bone marrow). The production of erythroblasts and red cells is markedly decreased, and it may be associated with decreased production of granulocytes (granulocytopenia) and platelets (thrombocytopenia) as well. Aplastic anemia may be idiopathic or secondary due to bone marrow damage by toxins, radiation, or immunologic factors.