Intrinsic red blood cell abnormalities Defects intrinsic to the RBC that can cause hemolysis involve abnormalities of the following: RBC membrane Cell metabolism Hemoglobin structure Abnormalities include hereditary cell membrane disorders (eg, hereditary spherocytosis), acquired cell membrane disorders (eg, paroxysmal nocturnal hemoglobinuria), disorders of RBC metabolism (eg, glucose-6-phosphate dehydrogenase (G6PD) deficiency), and hemoglobinopathies (eg, sickle cell disease, thalassemias).