Evaluation of a rapid, reliable, and inexpensive screening test for the serological diagnosis of human brucellosis.

In many laboratories the serological diagnosis of brucellosis is based on a tube agglutination test requiring incubation for two days and therefore causing delay in reporting of results. A slide agglutination test using an acidified, rose Bengal colored antigen that can be read after only 4 min was evaluated for its usefulness as a screening test for the presence of agglutinins in human sera. In sera of patients with culturally proven brucellosis or serological evidence for active infection the sensitivity of the slide agglutination test was 100%. Of 97 tube agglutination-negative sera none was positive in the slide test. From these results it was concluded that sera can be tested by the slide agglutination test which is quicker, easier to perform, and less expensive than the tube agglutination test. If positive, it is followed by a tube agglutination test which gives quantitative information and is necessary to follow the course of an infection.