The ASO titer tends to rise a week following infection and peaks at 3 to 5 weeks, begins to fall at 8 weeks, and returns to preinfection levels at around 8 months. Stronger ASO responses tend to occur with throat infection than skin infection, possibly because free cholesterol present in skin binds to streptolysin O, thereby decreasing its immunogenicity. Qualitative and semi-quantitative determination of anti-streptolysin-O antibodies (ASO) in serum can be performed using a rapid latex agglutination test.