Syphilis RPR is a rapid plasma reactin ring card test. When the syphilis spirochete infects the human body about 4 to 10 weeks later, a certain number of non-specific antibodies against lipid-like antigens can be produced in the serum, mainly IgG and IgM. These antibodies are mainly anti-cardiolipin antibodies, which are characterized by their relatively late appearance and are often negative in the early stages of stage I syphilis. These antibodies can be detected by immunological methods, and the syphilis RPR test is used to determine whether the body is infected with the syphilis spirochete by detecting the presence or absence of these two antibodies in the serum. This test is characterized by high sensitivity but poor specificity.