A general term for the destruction of red blood cells (RBCs). Hemolysis can occur for many reasons, including incompatible antibodies (as in hemolytic transfusion reactions and autoimmune hemolytic anemias), mechanical reasons (damaged heart valves or thrombotic microangiopathies), infections (malaria, babesiosis), enzyme deficiencies (G6PD), drugs (penicillins, cephalosporins), hemoglobin abnormalities (sickle cell disease), or RBC membrane defects (hereditary spherocytosis, McLeod syndrome), just to name a few! We commonly divide hemolysis into intravascular and extravascular categories for ease of understanding.