Final answer:
Serologic testing for S. pyogenes should compare acute and convalescent specimens collected 2 weeks apart.
Step-by-step explanation:
The serologic testing for S. pyogenes should compare acute and convalescent specimens collected 2 weeks apart. This interval is necessary because it takes time for the body to develop detectable levels of antibodies after an infection. By comparing the antibody levels in the acute and convalescent specimens, we can determine if there has been a significant increase in antibody titer, indicating a recent infection.