In the clinic, many patients will take the results of the four rheumatic tests, suggesting that the anti-O is increased, at this time many people are not calm, always think that there is rheumatic disease. Today, let’s get to know what anti-O is. Definition: A metabolite produced by Streptococcus haemolyticus can lyse red blood cells, so this product is named “O” haemolysin, after human infection with group A haemolytic streptococcus, “O” haemolysin exists in the body as an antigenic substance. In order to measure the amount of antibodies that can neutralize streptococcal hemolysin “O”, it is called the anti-streptococcal hemolysin “O” test. Through the above definition, we all understand the origin of anti-O, then it is very good to understand why sometimes this indicator will be high in the blood test, if you have an upper respiratory tract infection within six months, you may have an increased anti-O, but it can not be said that anti-O is necessarily high. “If there is no joint pain, no heart discomfort, you can temporarily observe, do not need to use drugs, the most standard is of course to listen to the advice of the primary care doctor, whether the need for treatment.