The relevance of the anti-human globulin (Coombs) test and the complement-fixation test in the diagnosis of brucellosis.

The relationship between the serological findings for brucellosis and the epidemiological factors has been studied in veterinary surgeons in Northern Ireland. The anti-human globulin (Coombs) test and the complement-fixation test for brucella were used in two groups of veterinary surgeons, those self-employed and those employed by the Ministry of Agriculture.Significant serological differences were found to exist between the two groups. Those in private practice showed changes related to age, cattle skin rash, reactions to S. 19 vaccine accidents and symptoms suggestive of brucellosis in the past or the last year. But those working for the Ministry only showed titre changes related to the length of their private practice experience before joining the Ministry. In neither group was there a relationship between serological findings and the type of milk drunk or any particular group of symptoms suggestive of brucellosis.The findings indicate that high titres to brucella by the Coombs and complement-fixation test can occur in people repeatedly exposed to infection at work. Titres which would be of diagnostic importance in the rest of the population may be of little diagnostic significance even when they are as high as 160 Coombs and 128 complement fixation.