This article was compiled by Dr. Wujian Ke based on the latest CDC guidelines for syphilis treatment released on June 5, 2015, and is published with permission (). Wujian Ke, Department of Venereal Diseases, Guangdong Provincial Dermatology Hospital, has accurate and reliable serologic test results for syphilis diagnosis and treatment response for most HIV (human immunodeficiency virus) infected patients. However, abnormal results (i.e., abnormally high or low, fluctuating titers) of non-syphilis spirochete antibody (e.g., RPR, TRUST) tests may occur regardless of HIV infection status. When serologic tests are inconsistent with results clinically suggestive of early syphilis, treatment of patients at risk for syphilis infection is recommended, and confirmation using other tests (e.g., skin tissue biopsy and PCR) is recommended. Cerebrospinal fluid (CSF) white blood cell counts are usually elevated (>5 white blood cell count [WBC]/cubic millimeter) in HIV-infected patients. Therefore, in HIV-infected patients suspected of having neurosyphilis, a higher CSF white blood cell count (> 20 WBC/mm3) needs to be used as a threshold to improve the specificity of the neurosyphilis diagnosis. This article is published with permission from Dr. Wujian Ke (). If you have any questions regarding this article, please visit my homepage ( )