Evaluation of unexplained hemolytic anemia

TMA: thrombotic microangiopathy (eg, thrombotic thrombocytopenic purpura [TTP], hemolytic uremic syndrome [HUS], drug-induced TMA); AIHA: autoimmune hemolytic anemia; DAT: direct antiglobulin (Coombs) test; G6PD: glucose-6-phosphate dehydrogenase; PK: pyruvate kinase; PNH: paroxysmal nocturnal hemoglobinuria; PCH: paroxysmal cold hemoglobinuria; DIC: disseminated intravascular coagulation; LDH: lactate dehydrogenase.
* Evidence of hemolysis includes increased reticulocyte count that is not due to active bleeding, recent correction of iron deficiency or nutritional anemia, or erythropoietin administration; spherocytosis; low haptoglobin; high LDH and indirect (unconjugated) bilirubin.
¶ Inherited intracorpuscular defects include hemoglobinopathies such as thalassemia or sickle cell disease; enzymopathies such as G6PD or PK deficiency; and membrane defects such as hereditary spherocytosis, elliptocytosis, or stomatocytosis.