Avoid the incorrect forms Coomb and Coomb's. a test for detecting sensitized erythrocytes in erythroblastosis fetalis and in cases of acquired immune hemolytic anemia: the patient's erythrocytes are washed with saline to remove serum and unattached antibody protein, then incubated with Coombs anti-human globulin (usually serum from a rabbit or goat previously immunized with human globulin); after incubation, the system is centrifuged and examined for agglutination, which indicates the presence of so-called incomplete or univalent antibodies on the surface of the erythrocytes.