Syphilis is a sexually transmitted disease that has a high incidence and is on the rise. Some people are first found to be positive for syphilis during a physical, pre-surgery, marriage or pregnancy test, but the patient reports no symptoms related to syphilis either in the past or at the time of the visit. In this case, it is very confusing whether treatment is needed, whether it is contagious, whether it is necessary to isolate the patient from her family, whether a woman of childbearing age can have a pregnancy, whether a positive syphilis serology found during a pregnancy test can continue the pregnancy and the risk to the fetus, and whether a newborn found to have a positive syphilis serology should be diagnosed as congenital syphilis and whether treatment is needed. The diagnosis of syphilis requires two indicators, 1. specific syphilis spirochete antigen serologic test (TPPA/TPHA) and 2. non-syphilis spirochete antigen serologic test (TRUST/RPR). TPPA is a qualitative test, also called a confirmatory test, if the test result is positive (excluding false positive cases) indicates that the syphilis spirochete has been infected, this test cannot be used to determine whether it is infectious and whether treatment is needed. Generally speaking, this antibody will not be negative even after treatment and will be carried for life, but it is not as protective as the hepatitis B antibody, which means that after syphilis is cured, if you come into contact with a syphilis patient again, you can develop the disease again. TRUST is a quantitative test that shows titers such as 1:2, 1:4, 1:8, 1:16, etc. as long as the test result is positive (excluding false positives). This test is used to determine whether the disease is infectious, whether treatment is needed, and to observe the efficacy of the treatment. In most patients, after regular treatment, the titer will gradually decrease until it turns negative. Question 1: How to determine whether the treatment is effective? A: It takes some time for the TRUST titer to drop and turn negative after anthelmintic treatment. If the titer drops 4 times or 2 titers, it means that the treatment is successful, otherwise, it is considered a failure and treatment should be restarted and the reason for the failure should be found. Question 2: How long does it take for TRUST to turn negative? A: Most patients can have a negative TRUST within one year after regular anthelmintic treatment, but some patients need 2 years to have a negative TRUST. If it is still not negative for more than 2 years and neurosyphilis is ruled out, the syphilis serology is considered fixed, which is not uncommon in clinical practice. The syphilis serology can be fixed without further treatment. Question 3: How long does syphilis need to be followed up? Since syphilis has the possibility of recurrence, regular follow-up is required after treatment, at least for 3 years. The first year is every three months, the second year is every six months, and the third year is at the end of the year. No recurrence for three consecutive years is required to determine complete clinical and laboratory cure. Question 4: How to correctly interpret the syphilis test results? A: Regarding the syphilis test results, the following situations are common: 1. TPPA positive, TRUST negative: there are the following possibilities: 1) early syphilis, that is, at the beginning of the disease, the body has not yet formed antibodies that can be detected by the TRUST test. In this case, if the test is repeated after three weeks, TRUST will turn positive. ②Cured, syphilis has been treated and the TRUST has turned negative. ③Self-healing, after infection with syphilis spirochetes, although not treated, but due to the strong immunity of the body, natural healing can occur, just like the infection with hepatitis B virus, the body produces antibodies but does not develop disease. Very late syphilis, in the late stage of syphilis such as neurosyphilis or cardiovascular syphilis, TRUST can be negative. ⑤ Combined HIV infection, syphilis combined with AIDS, syphilis serology tests can be negative. 2, TPPA positive, TRUST titer <1:8: There are the following possibilities: ① early syphilis, TRUST titer will increase significantly if this case is rechecked after three weeks. If the titer is below 1:8 for 2 years and neurosyphilis can be ruled out, the syphilis serology is considered fixed and can be left untreated. 3.TPPA positive, TRUST titer >1:8: Generally considered as current syphilis, which is infectious and requires active syphilis treatment and regular follow-up, at least 3 years. Women of childbearing age should not be pregnant during this period. 4.TPPA negative, TRUST negative: There are the following possibilities, which are completely normal and not infected with syphilis spirochetes, so you can rest assured. In the very early stage of the disease, that is, the body has not yet formed enough antibodies to be detected by the laboratory. If there is high-risk behavior, it is recommended to retest after three weeks. In the case of co-infection with HIV, syphilis serology may be negative. In this case, if the rash is typical, the diagnosis of syphilis can be confirmed by clinical manifestations. The diagnosis of syphilis should not be made blindly based on a single test, but should be analyzed in the context of the patient’s history of infection, clinical manifestations, previous treatment, and sexual partners, or else there will be misdiagnosis and overtreatment. Especially in the case of positive syphilis tests in women of childbearing age, during pregnancy and in newborns, it is necessary to evaluate carefully and give a scientific and reasonable decision. For syphilis, while emphasizing early diagnosis and treatment, it is necessary to prevent over-exaggeration of the disease and over-treatment, which may cause unnecessary financial burden and psychological harm to patients and their families.