Evaluation of unexplained hemolytic anemia

AIHA: autoimmune hemolytic anemia; DAT: direct antiglobulin (Coombs) test; DIC: disseminated intravascular coagulation; G6PD: glucose-6-phosphate dehydrogenase; LDH: lactate dehydrogenase; PCH: paroxysmal cold hemoglobinuria; PK: pyruvate kinase; PNH: paroxysmal nocturnal hemoglobinuria; TMA: thrombotic microangiopathy (eg, thrombotic thrombocytopenic purpura [TTP], hemolytic uremic syndrome [HUS], drug-induced TMA).

* Evidence of hemolysis includes:

• Spherocytosis
• Low haptoglobin
• High LDH
• High indirect (unconjugated) bilirubin
• Increased reticulocyte count that is not due to active bleeding, recent correction of iron deficiency or nutritional anemia, or erythropoietin administration

¶ Inherited intracorpuscular disorders include:

• Hemoglobinopathies such as thalassemia or sickle cell disease
• Enzymopathies such as G6PD or PK deficiency
• Membrane disorders such as hereditary spherocytosis, elliptocytosis, or stomatocytosis