[Comparative study of antistreptolysin O, anti-streptokinase and anti-streptozyme antibodies and antibodies against polysaccharides of group A Streptococcus].

A microagglutination test for antibody to streptococcal group A polysaccharide (APA) was compared with the anti-streptolysin O (ASO), anti-streptokinase (ASK) and streptozyme (STZ) tests in 162 human sera. Two or more of the following results were considered evidence of a recent streptococcal infection: ASO titre greater than or equal to 333 UI; ASK titre greater than or equal to 160 UI; STZ titre greater than or equal to 200. Sensitivity of the APA test was 70% and it detected 10 sera that would have been missed if the ASO test had been the only test performed. The APA test appears to be particularly useful in laboratories which rely solely on the ASO test for serological evidence of a streptococcal infection.