Mycoplasma pneumoniae MP, is an antibody test for Mycoplasma pneumoniae. This test is called passive agglutination, mainly to detect Mycoplasma pneumoniae infection, the sensitivity is very high, and easy, fast, cheap, it is used for routine clinical testing and screening. The current normal value is 1:40, if it is greater than 1:40 there is a weak positive, if it is greater than 1:80, it is a positive Mycoplasma pneumoniae antibody test. If the Mycoplasma pneumoniae test is positive, it does not indicate an acute infection with Mycoplasma pneumoniae. Mycoplasma pneumoniae antibody infections usually appear in 7-10 days, with long-term antibodies appearing in about 20 days, and short-term IgM antibodies appearing in 7-10 days. This IgM antibody can last up to one year, and even up to two years has been recorded. Therefore, to determine whether this patient has an acute Mycoplasma pneumoniae infection, we have to analyze and judge according to his clinical symptoms.