A passive hemagglutination test for the detection of Brucella infection.

An improved method of coupling a soluble complex, ABS, isolated from B, abortus to sheep red blood cells by chromic chloride in the presence of barbital buffer resulted in a highly specific and reliable passive hemagglutination test for the diagnosis of human and animal brucellosis. No false positive results have been found so far in more than 2000 control sera from known brucellosis-free patients or animals. On the other hand, with over 1800 test sera from patients or animals with Brucella infections, there were no false negative results, in contrast with tube agglutination or complement fixation tests.