(Koomz )
[R.R.A. Coombs, Brit. immunologist, 1921-2006]
A laboratory test for the presence of antibodies, usually blood type antibodies, in serum. The patient's serum is incubated with red blood cells (RBCs) with known antigenic markers; if antibodies to the antigen are present in the serum, they bind with the RBCs. When antihuman globulin is added, RBC clumping (agglutination) occurs. The test is used for crossmatching blood before transfusions to ensure that no antigen-antibody reactions will occur, and in suspected cases of hemolytic anemia, to identify specific autoantibodies to RBCs.