Low red blood cells and red blood cell pressure are the low number of red blood cells in the peripheral blood and the ratio of red blood cells to blood volume, a condition commonly seen in all types of anemia. Regardless of the type of anemia, low erythrocyte and erythropoietic pressure can occur. The most common types of anemia are iron deficiency anemia and megaloblastic anemia, both of which are nutritional anemias in which the lack of the necessary raw materials for hematopoiesis prevents the normal production of red blood cells and reduces their number, resulting in low red blood cell and red blood cell pressure. In addition, when the hematopoietic stem cells of the bone marrow are diseased, such as aplastic anemia, acute leukemia, myelodysplastic syndrome, congenital anemia, and pure red blood cell aplastic anemia, low erythrocyte and erythrocyte pressure product may also occur due to decreased proliferation of bone marrow hematopoietic stem cells and decreased erythropoietic cell production. The last condition is when there is excessive destruction of red blood cells in the peripheral blood, such as autoimmune hemolytic anemia, where low red blood cell count and pressure volume also occur due to the destruction and reduction of red blood cells.