Immunodiffusion method for identification of group A streptococci.

The development of a method suitable for identification of group A streptococci by microprecipitation in gels is described. The method is based on preparation of specific sera containing high antibody levels agains the antigenic determinant characteristic of group A streptococcal polysaccharide. In a comparative study with a counterimmunoelectrophoresis method, the proposed test proved to be specific, easily read, and less complicated. Results were obtained in 2 h.