The Coombs test checks the blood to see if it contains certain antibodies. Antibodies are proteins that your immune system makes when it detects that something may be harmful to your health.
Doctors use the indirect Coombs test, also called IAT, to prevent problems. They’ll check your blood before you get a transfusion to make sure it doesn’t have antibodies that would react badly to the donated blood. It’s part of the “type and screen” process.
An abnormal result in an indirect Coombs test means you have antibodies circulating in your bloodstream that could cause your immune system to react to any red blood cells that are considered foreign to the body — particularly those that may be present during a blood transfusion.
