[A rapid method of grouping beta-hemolytic streptococci using extemporaneous coagglutination]

Extemporaneous coagglutination procedure for the serological grouping of beta-hemolytic streptococci is reported. Streptococcal group antigens were extracted with nitrous acid. 250 strains of groups A, B, C, F and G streptococci were tested with this method. An agreement of 100% was found between this method and the Lancefield capillary precipitation procedure. Extemporaneous coagglutination method was found to be rapid, reliable, easy and economical and could be adopted in any routine diagnostic laboratory.