Clinical Utility

Streptolysin O is a hemolysin produced by group A streptococci. In an infected individual Streptolysin O acts as a protein antigen to which the patient mounts an antibody response. A rise in titer begins about 1 week after infection and peaks 2-4 weeks later. In the absence of complications or re-infection, the ASO titer will usually fall to preinfection levels within 6-12 months.