Syphilis is a sexually transmitted disease that seriously endangers human health, and the incidence of syphilis has increased year by year in recent years, with 419,000 syphilis cases reported nationwide in 2014 [1]. The incidence of syphilis serofast reaction or sero-resistance in syphilis patients after treatment is high, and the incidence by syphilis stage is 3.80% ~ 15.20% for stage 1 syphilis, 11.64% ~ 35.80% for stage 2 syphilis, 45.02% ~ 45.90% for stage 3 syphilis, and 27.90% for latent syphilis. 45.90%, and latent syphilis 27.41% ~ 40.50% [2-5]. Serum fixation has become a difficult problem in the clinical management of syphilis. A. Definition There is no clear definition of syphilis serum fixation, and the views of domestic and foreign experts are summarized as follows: ① After anti-syphilis treatment, most of the non-syphilis spirochete serological tests [such as rapid plasma reactin ring card test (RPR)] can be turned negative, but there are a few patients whose serum reaction titer gradually decreases to a certain level and then no longer decreases and is maintained at a low titer for a long time. Low titer, that is, the phenomenon of serum fixation or called serum resistance, the criteria are generally considered 2 years after treatment of early syphilis, more than 2 years after treatment of late syphilis seropositivity still remains positive [6]; ② syphilis patients after a sufficient amount of anti-syphilis treatment, in 1 ~ 2 years non-syphilis spirochete antigen serologic test has not turned negative, or titer does not decline [7]; ③ early syphilis patients after anti-syphilis treatment (3) patients with early syphilis who have been treated with anti-syphilis and followed up for a prescribed period of time, the serum still does not turn negative, which is called serum fixation; 1 year after early syphilis treatment or 2 years after late syphilis treatment the serum reactin test has not turned negative, which is serum fixation [8]; (4) syphilis patients with regular syphilis treatment and adequate follow-up (1 year for phase I syphilis follow-up, 2 years for phase II follow-up, and 3 years for late follow-up), the RPR is maintained at a low titer for a long time, or even accompanied by a lifetime Not turn negative [9]; ⑤ early syphilis patients after 6 months of standardized syphilis treatment, some patients have not yet turned negative serum reactin test, but the antibody titer still has a decreasing trend, at this time should not be prematurely determined as serum fixation, serum reactin antibody titer to a certain level no longer decreases for more than 3 months, can be considered as serum fixation [10]; ⑥ syphilis patients by standardized syphilis treatment after the disappearance of clinical manifestations, the Early syphilis 6 months, late syphilis 12 months, the serum reactive element test still does not turn negative [11]; (7) syphilis patients after standardized anti-syphilis treatment and adequate follow-up (generally 6 ~ 12 months), non-syphilis spirochete antigen serological test [such as RPR, toluidine red unheated serological test (TRUST)] titer only decreased by less than 2 dilutions or continued to remain positive but not treatment failure (Treatment failure is defined as a fourfold or greater increase in the titer of a non-syphilis spirochete antigen serologic test after treatment) [12-13]. The main disagreement between the above definitions is the variable follow-up time after standardized treatment, ranging from six months, one year to two years. We believe that serological fixation of syphilis can be defined as a patient with syphilis who has undergone standardized anti-syphilis treatment and adequate follow-up (1 year for stage I syphilis, 2 years for stage II syphilis, and 3 years for advanced syphilis), and whose non-syphilis spirochete serological test has been maintained at a certain titer (usually 1:8 or less, but more than 1:8 is not uncommon) for more than 3 months, excluding reinfection, neurosyphilis, cardiovascular syphilis, and biological The serum fixation of syphilis is defined as false positive. It is generally accepted that serum fixation and serum resistance are conceptually compatible, but serum fixation is more commonly used. The mechanism by which syphilis serofixation occurs is not fully understood. There are many factors that may influence the serologic response of patients after treatment, such as younger, earlier staging, fewer sexual partners, higher baseline titers, and better recovery of serologic response in patients with Jarisch-Herxheimer reaction after initial treatment, and vice versa [14-15]. It may also be related to the type, dose and route of administration of the initial treatment [16-17]. The possible mechanisms of syphilis serum fixation include: alteration of syphilis spirochete membrane peptide antigens, lipoproteins and genes leading to inability to be cleared by the body’s immunity, abnormalities in the body’s immunity, including immune imbalance and immunosuppression, disorders of T-cell subsets, natural killer (NK) cells and cytokine secretion, etc. [18-23]. There is insufficient evidence-based medical evidence to assess the harms of syphilis serofixation, and it is uncertain whether syphilis serofixation increases the risk of recurrence or progression to advanced syphilis, and whether additional penicillin therapy is beneficial [24-25]. Persistent positive syphilis serologic reactions have mainly psychological and psychiatric effects on patients, who may suffer from depression, anxiety and other adverse psychological states due to concerns about prognosis and transmission, social discrimination, etc [26-27]. IV. Treatment Because of the high incidence of syphilis serofixation, the management of such patients has now become a difficult clinical problem. Early diagnosis and timely standardized treatment are important measures to prevent syphilis serum fixation. A detailed medical history should be obtained at the time of initial syphilis treatment, including the history of sexual contact (time of infection, syphilis infection status of sexual partners, recent risky sexual behavior, etc.) and history of previous treatment (time of starting treatment, type of drugs used, duration and dosage, follow-up, etc.), so that the post-treatment serologic response of patients can be predicted [14-16]. During follow-up, cerebrospinal fluid testing is recommended for those identified with syphilis serofixation to rule out neurosyphilis, with multiple iterations if necessary [28-29]. HIV testing should also be performed to rule out HIV infection. Cardiovascular syphilis and other visceral syphilis also need to be excluded by appropriate tests [30]. False-positive syphilis serology should also be excluded. Patients with fixed syphilis serology need to be analyzed and counseled [27]. Patients who have received adequate anti-syphilis treatment and adequate follow-up, if there is no recurrence of clinical symptoms, and neurological examination, cerebrospinal fluid examination and other relevant examinations exclude neurological and other visceral systemic damage, and the non-syphilis spirochete serology test maintains a low titer of 1:8 or less for a long time, treatment may not be necessary, but regular follow-up (usually every 6 months) is required. It is recommended to add syphilis spirochete-specific IgM antibody testing [31-32], which can be used as a marker for syphilis recurrence and reinfection [32], if available. A fourfold or more elevated titer in the non-syphilis spirochete serological test found during follow-up indicates recurrence or reinfection and requires re-treatment. Patients with syphilis serofixation need to weigh the pros and cons to choose whether to become pregnant or not, and if pregnant they need to be followed up regularly and if necessary, preventive treatment can be considered [33], i.e., treatment according to the norms for syphilis in pregnancy during pregnancy. Studies have shown that treatment of pregnant syphilis patients according to a standardized anti-syphilis regimen can block the occurrence of congenital syphilis in 98.5% to 100% of cases [34-36]. Chinese medicine can be used as an adjunctive treatment for patients with syphilis serofixation. According to TCM, the etiology of syphilis serum fixation is mainly due to deficiency of positive qi, internalization of evil toxins, and deficiency of positive and evil attachment. The principle of treatment is to tonify the spleen and benefit the qi, and detoxify the dampness. Astragalus membranaceus, Rhizoma Atractylodis Macrocephalae, Radix et Rhizoma Polygonati, Poria tulipifera, Rhizoma Umbelliflorum, Radix et Rhizoma Bupleurum, Dandelion and Glycyrrhiza glabra can be used for treatment [37].