Coombs tests

(redirected from direct Coombs tests)

Coombs tests

laboratory tests that reveal certain antibody-antigen reactions; used in differentiating between various types of hemolytic anemias, for determining minor blood types, and for testing for alloimmune hemolytic disease of the newborn. Called also antiglobulin test.

direct Coombs tests
the test used to detect the presence of cell-bound antibodies that may damage erythrocytes but will not cause visible agglutination. The red cells are washed free of serum and unbound antibody, and antiglobulin (species-specific antiserum directed against antibodies) is added. Agglutination indicates the presence of antibody. Clinically its most important use is in the diagnosis of alloimmune hemolytic anemia of the newborn (Rh disease in humans) and autoimmune hemolytic anemia.
indirect Coombs tests
detects antierythrocyte antibodies in the serum. Test serum is incubated with red blood cells. The cells are then washed and mixed with antiglobulin serum. Agglutination indicates the presence of antibody in test serum. Supernatant from colostrum may be used instead of serum.