Immune hemolytic anemia is a disorder characterized by anemia due to premature destruction of red blood cells by the immune system.

Immune hemolytic anemia occurs when antibodies form against the body's own red blood cells. The antibodies will destroy the blood cells because these blood cells are recognized as foreign material within the body. The antibodies may be acquired by blood transfusion, pregnancy (if the baby's blood type is different from the mother's), as a complication of another disease, or from a reaction to medications.

If the cause of antibody formation is disease or medication, it is referred to as secondary immune hemolytic anemia. The cause may also be unknown, as in idiopathic autoimmune hemolytic anemia, which accounts for one-half of all immune hemolytic anemias. The disease may start quite rapidly and be very serious, or it may remain mild and not require specific treatment. Risk factors are related to the causes.

• Fatigue
• Pale or yellow skin color
• Shortness of breath
• Rapid heart rate
• Dark urine
• Enlarged spleen

• Positive direct or indirect Coombs' test
• High bilirubin levels
• High LDH (enzymes whose levels rise as a result of tissue damage)
• Low serum haptoglobin
• Hemoglobin in the urine
• Elevated absolute reticulocyte count
• Low red blood cell count (RBC) and hemoglobin