Positive syphilis serology: interpretation and follow-up after treatment
BioMG follows French guidelines. Adapt it to the guidelines and the tests available where you practise.
Positive treponemal test: interpret and complete
Laboratory tests (at diagnosis)
- HIV serology
- Hepatitis B serology (HBsAg, anti-HBs, anti-HBc), if status unknownif needednon-French guidelineHepatitis B immunity not documented: the European guideline asks for the status to be assessed and for vaccination if needed [2].
- Hepatitis C serology (if risk factor)if needednon-French guidelineRisk factor according to local epidemiology (men who have sex with men, drug use, multiple partners, etc.) [2].
On self-collected sample or first-catch urine (sites depending on sexual practices)
- Chlamydia trachomatis and Neisseria gonorrhoeae NAAT (PCR)
In 1 month
- Repeat syphilis serology (treponemal test and titrated non-treponemal test)if needednon-French guidelinePositive treponemal test, negative non-treponemal test, no chancre and no documented previous treatment: repeat both tests after 1 month so as not to miss a very recent syphilis [2]. Same approach in pregnant women [2].
Also consider
Do not order
- Titration of the treponemal test (quantitative TPHA, EIA index) to judge activity or cure: the treponemal test remains positive for life and its titre does not predict response to treatment [2,4].
- Anti-treponemal IgM to date or stage syphilis: their sensitivity is low and they allow neither the stage to be determined nor the duration of treatment to be chosen [2].
- IgG Western blot outside pregnancy: no major added value over the other treponemal tests [2]; the French laboratory fee schedule (NABM) reserves it for pregnant women [3].
- Routine lumbar puncture, including in HIV-positive patients, in early syphilis without neurological, ocular or auditory signs [2].
Follow-up after treatment of early syphilis
On the day of treatment
- Syphilis serology with titrated non-treponemal test (reference titre), if the non-treponemal test at diagnosis is more than 7 days oldif neededIf the injection takes place more than 7 days after the diagnostic non-treponemal test, repeat it on the day of the injection, because it changes rapidly [5]: this is the baseline titre for follow-up [2].
At 3 months
- Titrated non-treponemal test (VDRL or RPR), same technique, same laboratory
- HIV serology (if the test at diagnosis may have fallen within the window period)if needednon-French guidelineEarly syphilis: the infection is recent, and the HIV serology at diagnosis may have preceded seroconversion. The ASHM (Australia) proposes repeating HIV screening after the window period, at the 3-month visit [7]; the CDC has the HIV test repeated at 3 months after primary or secondary syphilis in areas of high HIV prevalence [4]. The 2025 French recommendation provides at 3 months only for the non-treponemal test [5].
At 6 months
- Titrated non-treponemal test (VDRL or RPR), same technique, same laboratory
At 12 months
- Titrated non-treponemal test (VDRL or RPR), same technique, same laboratory
At 24 months
- Titrated non-treponemal test (patient living with HIV or at high risk, if still positive at 12 months)if neededPatient living with HIV or at high risk of recurrence whose serology is still positive at 12 months: a final check at 24 months may be discussed [5].
- State “follow-up of syphilis treated on …, initial titre …”: the laboratory tests the previous serum in parallel if possible.
Do not order
Follow-up after treatment of late syphilis
On the day of treatment
- Syphilis serology with titrated non-treponemal test (reference titre), if the non-treponemal test at diagnosis is more than 7 days oldif neededIf the injection takes place more than 7 days after the diagnostic non-treponemal test, repeat it on the day of the injection, because it changes rapidly [5]: this is the baseline titre for follow-up [2].
At 6 months
- Titrated non-treponemal test (VDRL or RPR), same technique, same laboratory
At 12 months
- Titrated non-treponemal test (VDRL or RPR), same technique, same laboratory
At 24 months
- Titrated non-treponemal test (VDRL or RPR), same technique, same laboratory
- State “follow-up of syphilis treated on …, initial titre …”: the laboratory tests the previous serum in parallel if possible.
Do not order
Sources (7)
- Santé publique France. Surveillance des infections sexuellement transmissibles bactériennes en médecine générale, France, 2020-2022 (réseau Sentinelles). Article en ligne, consulté le 24/10/2026.
- Janier M, Unemo M, Dupin N, Tiplica GS, Potočnik M, Patel R. 2020 European guideline on the management of syphilis. J Eur Acad Dermatol Venereol. 2021;35(3):574-88.
- Assurance maladie. Nomenclature des actes de biologie médicale (NABM), version 105 : actes 1256 à 1259 (syphilis) et 1250 (western blot IgG chez la femme enceinte).
- Workowski KA, Bachmann LH, Chan PA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1-187.
- Haute Autorité de santé, Conseil national du sida et des hépatites virales, ANRS-MIE. Recommandations de prise en charge des personnes ayant une syphilis. Recommandation de bonne pratique, validée par le Collège le 10 avril 2025.
- Kingston M, Apea V, Evans C, et al. BASHH UK guidelines for the management of syphilis 2024. Int J STD AIDS. 2024 (publication en ligne).
- Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine (ASHM). Australian STI Management Guidelines for Use in Primary Care : Syphilis. Page mise à jour le 15 octobre 2026, consultée le 29 octobre 2026.