Comparison of an agar-gel immunodiffusion test with other serological methods for differentiating Brucella infected from vaccinated cattle.

An agar-gel immunodiffusion test was compared with other serological tests for detection of antibodies in the sera of 48 cattle vaccinated with Brucella abortus strain 19. Two hundred forty-two sera were tested over a 12 month period, and addition of positive reactions for each test resulted in totals of 170 for the card test, 74 for the standard tube-agglutination test, 71 for the 2-mercaptoethanol test, 64 for the dithiothreitol test and 22 for the agar-gel immunodiffusion test.