Altered myelogram refers to changes in the degree of bone marrow cell proliferation, bone marrow cell count, granulocyte-red ratio, and the ratio of hematopoietic cells in each system and stage. Bone marrow changes can occur in a variety of pathologies, and each disease that will have bone marrow changes will have a different bone marrow image. Bone marrow picture in aplastic anemia: hypoplasia or severe hypoplasia of bone marrow, decrease in the percentage of volume of hematopoietic tissue to adipose tissue (Vol%) (less than 34Vol%), and increase in adipocytes and stroma. Erythrocytes and granulocytes are reduced, megakaryocytes are significantly reduced or missing, lymphocytes are relatively increased, and non-hematopoietic cells such as plasma cells, mast cells, and reticulocytes are increased. Bone marrow picture of megaloblastic anemia: extremely active bone marrow proliferation, hematopoietic tissue area greater than or equal to 90Vol%, and reduced adipocytes. There is a diffuse infiltration of megaloblasts at different stages of development and a decrease in the granulocyte/red ratio. Iron deficiency anemia bone marrow picture: markedly active or extremely active bone marrow proliferation, hematopoietic tissue area 50~89Vol% (or higher), predominantly erythropoietic cells at different stages of development, and decreased granulocyte/red ratio. b, predominantly intermediate and late juvenile erythropoietic cells with small and dense nuclei, low cytosolic mass, and uneven margins. The diagnosis can be made by combining the medical history.