Lance field grouping of streptococci is done by using :

Lancefield classification Classification of β hemolytic streptococci into Group A to V (except I, J) on the basis of group specific C carbohydrate. Griffith classification Serological typing of Group A Streptococcus pyogenes on the basis of M proteins into types 1, 2, 3 etc. Group C Carohydrate Present in middle layer of cell wall. This antigen is an integral part of cell wall. Serological grouping of streptococci depend on C carbohydrate for which it has to be extracted from cell wall.