Anti-Streptolysin 0 antibody recognizes Streptolysin 0 (SL0), which is a membrane-damaging extracellular toxin produced by hemolytic streptococci. In the hemolytic streptococci infection, the antibodies to various proteins secreted from the bacteria such as toxins increase. The measurement of the Anti-Streptolysin 0 (ASLO) is widely used for diagnostic confirmation of hemolytic streptococci infection.