Coombs Indirect (Indirect Antiglobulin Test) details

The indirect Coombs test checks your blood plasma (rather than the surface of your own red blood cells, as the direct test does) for antibodies that could react against red blood cell antigens. It's used most commonly before blood transfusions, to screen for antibodies that might cause a transfusion reaction to donor blood, and during pregnancy, particularly to screen Rh-negative mothers for antibodies against Rh-positive blood, which can develop after exposure to a baby's Rh-positive blood and potentially affect future pregnancies. A positive result prompts further antibody identification testing to determine exactly which antibody is present and how significant it is.