Diagnosis of streptococcal infection: previous or recent

For the determination of streptococcal infection, it is necessary to test 3 antibodies, i.e., ASO, ASK and ADN-B at a time, and if 2 of the 3 titers are positive one can make diagnosis of fairly recent streptococcal infection, but if only one of the 3 titers are positive, previous or non-specific causes should be considered.