Syphilis is a common STD caused by syphilis spirochete infection. In addition to causing damage to the infected person itself, it can also be transmitted through the placenta causing miscarriage, premature birth, stillbirth and fetal syphilis, which is extremely harmful. At present, the clinical diagnosis is often tested for TPPA, RPR, TRUST, etc. TPPA: This test is not specific and is mainly used for the diagnosis of syphilis, and a positive result can clarify the diagnosis. RPR and TRUST are non-specific tests for syphilis, which are often used as diagnostic screening for syphilis and as indicators for observing the efficacy of treatment and judging recurrence. After effective treatment, most patients can become negative for RPR and TRUST, while a small number of patients with fixed sera may still be positive or have a certain titer. However, TPPA can be positive for life even after cure. Therefore, the result of treatment can only be the conversion or titer decrease of RPR or TRUST, while TPPA cannot achieve the effect of conversion. Patients who are cured after regular treatment need to be followed up regularly for three years for RPR or TRUST, every three months in the first year, every six months in the second year, and at the end of the third year, and are considered to be clinically cured if there is no increase in titers in three years.