In Ottawa, Canada, we initiated protocols to include non-serologic syphilis testing, as direct fluorescence antibody (DFA) for patients with syphilis symptoms. The purpose was to assess the ability of DFA to detect syphilis during acute infection and to determine if non-serologic testing could yield an increased number of syphilis diagnoses. We reviewed charts of patients of our local sexual health clinic for whom syphilis was suspected. A total of 69 clinical encounters were recorded for 67 unique patients, most of whom were male. The most common symptom was a painless genital lesion. Of the 67 patients, 29 were found to have a new syphilis diagnosis, among whom, 52% had positive syphilis serology and positive DFA, 34% had a positive syphilis serology and negative DFA, and 14% had negative syphilis serology and positive DFA. While DFA testing did not yield an abundance of new cases, it was useful to support findings from syphilis serology or confirm diagnosis where serology was negative. Where available, alternate non-serologic tests, such as nucleic acid amplification tests, should be considered above DFA due to its higher sensitivity for detecting syphilis in primary lesions; however, in clinical situations, when new syphilis infection is suspected, empiric treatment should not be delayed.

1. Public Health Ontario . Infectious disease trends in Ontario. Syphilis. 2021. Retrieved from https://www.publichealthontario.ca/en/data-and-analysis/infectious-disease/reportable-disease-trends-annually
Google Scholar2. Shah, D, Marfatia, YS. Serological tests for syphilis. Indian J Sex Transm Dis AIDS 2019; 40(2): 186–191. DOI: 10.4103/ijstd.IJSTD_86_19
Google Scholar | Crossref | Medline3. Public Health Agency of Canada . Canadian guidelines on sexually transmitted infections: Management and treatment of specific syndromes. 2013. Retrieved from https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines/sexually-transmitted-infections/canadian-guidelines-sexually-transmitted-infections-19.html
Google Scholar4. Public Health Agency of Canada . Canadian guidelines on sexually transmitted infections: Syphilis screening and diagnostic testing. 2020. Retrieved from https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines/syphilis.html
Google Scholar5. Singh, A, Romanowski, B. Syphilis: Review with emphasis on clinical, epidemiologic, and some biologic features. Clin Med Microbiol Rev 1999; 12(2): 187–209. DOI: 10.1128/CMR.12.2.187
Google Scholar | Crossref | Medline6. O’Byrne, P, MacPherson, P. Syphilis. BMJ 2019; 365: l4159. DOI: 10.1136/bmj.l4159
Google Scholar | Crossref | Medline7. Holmes, KK, Sparling, PF, Stamm, WE, et al. Sexually Transmitted Diseases. 4th ed. McGraw-Hill, 2007
Google Scholar8. Public Health Ontario . Laboratory Services: Syphilis, Serology. 2020. https://www.publichealthontario.ca/en/laboratory-services/test-information-index/syphilis-serology
Google Scholar9. Tsang, RSW, Morshed, M, Chernesky, MA, et al. Canadian public health laboratory network guidelines for the use of direct tests to detect syphilis in Canada. Can J Infect Dis Med Microbiol 2015; 26(Suppl A): 13A–17A. DOI: 10.1155/2015/685603
Google Scholar | Crossref | Medline10. Brown, DL, Frank, JE. Diagnosis and management of syphilis. AFP 2003; 68(2): 283–290. https://www.aafp.org/afp/2003/0715/p283.html
Google Scholar11. Theel, ES, Katz, SS, Pillay, A. Molecular and direct detection tests for Treponema pallidum subspecies pallidum: A review of the literature, 1964-2017. Clin Infect Dis 2020; 71(Suppl 1): S4–S12. DOI: 10.1093/cid/ciaa176
Google Scholar | Crossref | Medline12. Luo, Y, Xie, Y, Xiao, Y. Laboratory diagnostic tools for syphilis: Current status and future prospects. Front Cell Infect Microbiol 2021; 10: 574806. DOI: 10.3389/fcimb.2020.574806.
Google Scholar | Crossref | Medline13. Satyaputra, F, Hendry, S, Braddick, M, et al. The laboratory diagnosis of syphilis. J Clin Microbiol 2021; JCM.00100-21. doi: 10.1128/JCM.00100-21. Epub ahead of print.
Google Scholar | Crossref | Medline14. Centers for Disease Control and Prevention . Sexually transmitted diseases treatment guidelines, MMWR Recomm Rep 2015; 64(RR-03): 38–39.
Google Scholar15. Ottawa Public Health . Cases of Infectious Diseases of Public Health Significance in Ottawa. 2020. Retrieved from https://www.ottawapublichealth.ca/en/reports-research-and-statistics/infectious-diseases.aspx#cases
Google Scholar16. O’Byrne, P, Phillips, JC, Campbell, B, et al. Express testing in STI clinics: Extant literature and preliminary implementation data. Appl Nurs Res 2016; 29: 177–187. DOI: 10.1016/j.apnr.2015.06.003
Google Scholar | Crossref | Medline | ISI17. Ontario Ministry of Health . Syphilis: Provincial Case Definitions for Diseases of Public Health Significance. 2019. Retrieved from https://www.health.gov.on.ca/en/pro/programs/publichealth/oph_standards/docs/syphilis_cd.pdf
Google Scholar18. Ontario Ministry of Health . Infectious Diseases Protocol. 2020. Retrieved from https://www.health.gov.on.ca/en/pro/programs/publichealth/oph_standards/docs/protocols_guidelines/infectious_disease_protocol.pdf
Google Scholar19. Orser, L, O’Byrne, P, Bourgault, A, et al. Development of an algorithm to facilitate the clinical management of syphilis. J Am Assoc Nurse Pract 2020; 33(6): 476–483. DOI: 10.1097/JXX.0000000000000370
Google Scholar | Crossref | Medline20. Centers for Disease Control and Prevention . Sexually Transmitted Infection Treatment Guidelines. 2021. https://www.cdc.gov/std/treatment-guidelines/default.htm
Google Scholar21. Ross, C, Shaw, S, Marshall, S, et al. Impact of a social media campaign targeting men who have sex with men during an outbreak of syphilis in Winnipeg, Canada. Can Commun Dis Rep 2016; 42-2: 45–49. DOI: 10.14745/ccdr.v42i02a04
Google Scholar | Crossref22. Centre for Disease Control and Prevention . Syphilis Strikes Back. 2021. https://www.cdc.gov/std/saw/syphilisstrikesback/default.htm
Google Scholar23. Peterman, TA, Furness, BW. Public health interventions to control syphilis. Sex Health. 2015; 12(2): 126–134. DOI: 10.1071/SH14156
Google Scholar | Crossref | Medline24. Choudri, Y, Miller, J, Sandhu, J, et al. Infectious and congenital syphilis in Canada, 2010-2015. CCDR 2018; 44(2): 43–48. DOI: 10.14745/ccdr.v44i02a02
Google Scholar | Crossref25. Public Health Agency of Canada . Canadian Guidelines on Sexually Transmitted Infections. Primary Care and Sexually Transmitted Infections. 2013. Retrieved from https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines/sexually-transmitted-infections/canadian-guidelines-sexually-transmitted-infections-17.html
Google Scholar26. O’Byrne, P, MacPherson, P, Orser, L, et al. Clinical considerations and protocols for nurse-led PrEP. J Assoc Nurses AIDS Care 2019; 30(3): 301–311. DOI: 10.1097/JNC.0000000000000075
Google Scholar | Crossref | Medline27. Pathela, P, Braunstein, SL, Blank, S, et al. The high risk of an HIV diagnosis following a diagnosis of syphilis: A population-level analysis of New York City men. Clin Infect Dis 2015; 61(2): 281–287. DOI: 10.1093/cid/civ289
Google Scholar | Crossref | Medline28. Galvin, SR, Cohen, MS. The role of sexually transmitted diseases in HIV transmission. Nat Rev Microbiol 2004; 2: 33–42. DOI: 10.1038/nrmicro794
Google Scholar | Crossref | Medline | ISI29. Friedman, DS, O’Byrne, P. Extragenital testing increases case detection of gonorrhea and chlamydia: The impact of implementing nucleic acid amplification testing. CCDR 2020; 46(9): 285–291. DOI: 10.14745/ccdr.v46i09a06
Google Scholar | Crossref