Anemias might represent bone marrow failure as a primary disorder or as a result of drug or toxin action. Three disorders include aplastic anemia, pure red cell aplasia, marrow replacement with fibrotic tissue or tumor and anemias secondary to cancer. Tow mechanisms have been postulated for aplastic anemia: Immunologic suppression of hematopoiesis and damage to marrow stem cells. Iron deficiency anemia is a sign of underlying disease in itself. The major cause for iron deficiency in adults is blood loss (GI bleeding in men and GY bleeding in women), whereas in growing children and pregnant women dietary iron lack is more common. Malabsorption also can lead to iron deficiency. Megaloblastic anemia are anemias in which DNA synthesis is impaired, leading to delayed division of all rapidly proliferating cells including hematopoietic cell. The major cause of Megaloblastic anemia are folic acid or vitamin B12 deficiency. Acquired hemolytic disorders is causing anemia as red cell life span can become shortened in the course of infectious, malignant, cardiovascular, or immunologic diseases,. In most of these, hemolysis results from an extracorporeal abnormality such as related hemodynamics, antibody against red cell antigens, or exposure to toxins. Hemoglobinopathes is abnormal hemoglobins clinically presented with anemia and other symptoms. Sickle cell anemia, Unstable hemoglobin and Hemoglobin of altered oxygen affinity are resulting from abnormality in hemoglobin structure and function. Hemolytic anemia in Thalassemias result from mutation that affect globin synthesis in which hemoglobin that produced is less than normal in amount but structurally normal. Finally anemia can be caused due hemolysis resulting from red cell trauma. Red cell exposed to excessive mechanical stress interavascularly or during extracorporeal circulation can undergo fragmentation hemolysis