Anaemia resulting from reduced red cell survival time and haemolysis, either due to an intrinsic defect in the erythrocyte (hereditary spherocytosis or ellipsocytosis, enzyme defects, haemoglobinopathy) or an extrinsic damaging agent. For example autoantibody (autoimmune haemolytic anaemia), iso antibody, parasitic invasion of the cells (malaria), bacterial or chemical haemolysins, mechanical damage to erythrocytes.