How is Coomb's testing of BG?

Coombs tests are laboratory tests used to detect the presence of antibodies or complement proteins bound to the surface of red blood cells (RBCs). The direct Coombs test (direct antiglobulin test, DAT) detects antibodies or complement proteins attached to the patient's own RBCs in vivo. The indirect Coombs test (indirect antiglobulin test, IAT) detects antibodies in the patient's serum that may react with donor RBCs ex vivo. Coombs testing is particularly useful in diagnosing autoimmune hemolytic anemias and determining compatibility in blood transfusions