The TPPA/TPHA test is a syphilis-specific IgG antibody, which is positive for life once the antibody is produced, so the TPPA/TPHA is not tested during the follow-up period after the diagnosis of syphilis, and it does not turn negative with the cure of syphilis. However, there are some patients in whom RPR does not turn negative despite repeated penicillin treatment, and no clinical evidence of syphilis spirochete activity is found, called serum fixation, which we observe for a long enough time, although RPR is positive, but the clinical judgment is healed. In fact, the treatment of syphilis is based on years of clinical experience. Although penicillin is effective in treating syphilis and no drug resistance has been found for many years, there is no treatment plan that can guarantee a one-time cure for syphilis, and there is no test that can tell whether syphilis is cured or not at one time. Therefore, no matter what regimen is used to treat syphilis, it is important to follow up for 2-3 years to determine whether syphilis is cured by dynamic RPR changes. In general, after treatment with benzathine penicillin, the RPR turns negative and does not change for one year, or the RPR is less than 1:8 and does not change for 2 years, and then the syphilis is cured.