Antibodies are part of the immune system. They help your body fight germs, but sometimes they make mistakes and attack your body's healthy cells. In a Coombs test, your blood is drawn, and lab tests are done to look for antibodies that attack red blood cells. You may also hear it called an antiglobulin test or a red blood cell antibody screen.

The coombs test is one of the tests used to determine the cause of hemolytic anemia. The direct coombs test looks for antibodies attached to red blood cells. Antibodies can be produced by the body, caused by disease, or from a blood transfusion.