Inhibition of nonspecific streptococcal coagglutination reactions

Abstract

The reliability of latex coagglutination testing for the serological grouping of hemolytic streptococci is limited by the relatively high incidence of false-positive reactions. Pretreatment of streptococcal suspensions with antisera for the various groups that show clumping gives a specific inhibition of the latex agglutination with the true group; the other groups continue to agglutinate aspecifically. The method is rapid and easy to perform, allows the exact groups of those streptococci giving aspecific reactions and is a useful confirmatory test with monoreactive strains.