Microtiter indirect hemagglutination procedure for identification of streptococcal M-protein antibodies.

A number of investigators have attempted to utilize the hemagglutination system for detection of streptococcal type-specific antibody in human sera. Cross-reactions have made the procedure unreliable without cumbersome and time-consuming manipulation of the test sera. A method is described in which a microtiter indirect hemagglutination technique, using sensitized sheep erythrocytes, is sensitive, specific, and reliable for titration of type-specific antibody after naturally acquired or induced streptococcal infection.