Background Considering the unknown prevalence of neurosyphilis in West China, and the confusing diagnosis of neurosyphilis, the role of CSF_CXCL13 and syphilis serology was studied to provide a more accurate reference for the clinical detection and diagnosis of neurosyphilis.

Methods A retrospective data set I was used to investigate the prevalence of neurosyphilis, as well as the laboratory characteristics of 244 patients. Besides, to explore the diagnostic value of CSF_CXCL13 and syphilis serology for neurosyphilis, another 116 CSF_serum paired samples (data set II) were collected from 44 neurosyphilis and 72 non-neurosyphilis/syphilis patients.

Results About 6.25% (156 out of 2494) syphilis was neurosyphilis. When Treponema pallidum infection occurs, syphilis serology (sero_TRUST ≥1:16 and sero_TPPA titre ≥1:10240) can be good predictors of neurosyphilis, as well as syphilis CSF serology (CSF_TPPA ≥1:320, CSF_TRUST and venereal disease research laboratory). The sensitivity of serology in neurosyphilis can be complemented by CSF_CXCL13, which could be the therapy monitor of neurosyphilis.

Conclusion Due to the lack of ideal biomarkers for neurosyphilis, the importance of syphilis serology cannot be ignored, and their combination with CSF_CXCL13 or other biomarkers should be further investigated.