This test, which has been proposed for use in diagnosis of rheumatoid arthritis, depends upon the use of polyvinyl toluene or polystyrene latex particles serving as carriers of fraction II of serum (gamma globulin) in an agglutination reaction with patient's serum. The addition of latex particles mixed with gamma globulin is added to progressive dilutions of the serum to be tested. The resultant visible agglutination is read with the naked eye. Seventy-one per cent of the serums from 150 patients with rheumatoid arthritis gave positive agglutination. Of 250 patients with rheumatic fever and rheumatic heart disease, only 1.6% gave a positive agglutination test. The agglutination test is positive in a small percentage of other diseases, such as hyperglobulinemia and lupus erythematosus. The results of the latex test compare favorably with the hemagglutination test which employs sheep erythrocytes. The latter test is more difficult to perform and to control. Both tests are positive in a smaller percentage of individuals with juvenile rheumatoid arthritis, which has not been explained.
A simple latex slide test for rheumatoid arthritis using the gamma globulin in the patient's serum