A 72-year-old man who has recently had an aoic valve replacement now presents with pallor and fatigue. The red blood cell count is decreased, and schistocytes are repoed on examination of a peripheral blood smear. In addition, his indirect (unconjugated) bilirubin is significantly elevated. The cause of the anemia is likely
cold agglutinin disease. dietary deficiency. hereditary spherocytosis. mechanical disruption of red cells.