Lancefield grouping of streptococci is done by using-

β hemolytic Streptococcus is classified to group A-V based on C carbohydrate antigen (Lancefield classification) M protein is used to further classify group A Streptococcus (Griffith typing). Ref: Apurba Sastry’s Essentials of Medical Microbiology 1/e p221, Ananthanarayan 9/e p209