abortus Bang ring test

ABR test (screening for brucellosis in cattle) since Brucella agglutinins, as well as the organisms, are shed in the milk of infected cattle, a drop of hematoxylin-stained brucellae is mixed in a sample of pooled milk from the herd. After incubation, agglutinated bacteria are adsorbed by the globules of fat that rise to the surface to form a colored ring. Called also milk ring t.