In medicine, to evaluate and diagnose whether a patient has a disease caused by hemolytic streptococcus bacteria or not, the ASO test can be performed to measure the quantity of streptococcal antibodies present in the patient's blood. In addition to diagnosing diseases caused by hemolytic streptococcus bacteria, the ASO test is also used to diagnose other diseases such as arthritis, rheumatism, ... so what is the meaning of the ASO test?