Which tests,
when and why.
A page for navigating the international guidelines: for each infection, which test they indicate, on which sample and from when it is reliable. This is not a diagnosis, it is not personal advice and it does not replace a doctor.
See the tests indicated
Pattern of partners
Symptoms or diagnosis
Genitals
Partners’ genitals
What I do
Where the toys go
When to test
Answer the questions first.
With symptoms, or with a partner who has just been diagnosed, the guidelines set no interval at all: testing happens now, and the assessment is the doctor’s.
Which tests to take
HIV | Blood test () or Rapid finger-prick or oral-fluid test | |
Hepatitis B | Blood test Hepatitis B: no test needed with a complete vaccine course, according to the guidelines. The vaccination record will say (the booklet or an online profile), or a doctor can check. Under Italian law, anyone born in Italy from 1980 onwards is probably vaccinated. | |
Chlamydia and gonorrhoea | First-void urine Self-taken vaginal swab with new or multiple partners; under 25, once a year Self-taken rectal swab for receptive anal sex, if a shared toy goes into the rectum, or after fisting Self-taken throat swab (gonorrhoea only) for oral sex given to a penis, or if a shared toy goes into the mouth: routine among males with male partners, otherwise to be discussed with a doctor | |
Syphilis | Blood test right away Swab of the sore if there is a lesion | |
Hepatitis C | Blood test | |
Hepatitis A | right away Anti-HAV if acute hepatitis | For these infections the guidelines do not provide for routine testing after sex: there is no window period to wait out, and looking for them across the board, without a reason, is not recommended. They are looked for in two cases only: if symptoms appear (sores, discharge, itching, diarrhoea…) or if a partner has been diagnosed. In both, it is the doctor who decides which test to run. |
Genital herpes () | right away Swab of the lesion () if there is a lesion, while it is still visible | |
Mpox | right away Swab of the lesion () if there is a lesion | |
Trichomonas | right away Vaginal swab with symptoms or a partner who tested positive right away Urine (people with a penis) with symptoms or a partner who tested positive | |
Mycoplasma genitalium | right away Urine or swab, with resistance testing if symptoms persist | |
Gut infections | right away Stool test with diarrhoea after oro-anal contact | |
Scabies / pubic lice | right away Examination: diagnosed by sight with itching | |
For these infections the guidelines do not provide for routine testing after sex: there is no window period to wait out, and looking for them across the board, without a reason, is not recommended. They are looked for in two cases only: if symptoms appear (sores, discharge, itching, diarrhoea…) or if a partner has been diagnosed. In both, it is the doctor who decides which test to run. | ||
Blood draw | HIV test or HIV rapid finger-prick or oral-fluid test Syphilis Hepatitis C Only with symptoms right away Hepatitis A anti-HAV if acute hepatitis Hepatitis B Hepatitis B: no test needed with a complete vaccine course, according to the guidelines. The vaccination record will say (the booklet or an online profile), or a doctor can check. Under Italian law, anyone born in Italy from 1980 onwards is probably vaccinated. |
First-void urine | Chlamydia and gonorrhoea Only with symptoms right away Trichomonas for people with a penis with symptoms or a partner who tested positive Only with symptoms right away Mycoplasma genitalium urine or swab, with resistance testing if symptoms persist |
Vaginal swab | Chlamydia and gonorrhoea self-taken with new or multiple partners; under 25, once a year Only with symptoms right away Trichomonas with symptoms or a partner who tested positive |
Rectal swab | Chlamydia and gonorrhoea for receptive anal sex, if a shared toy goes into the rectum, or after fisting |
Throat swab | Chlamydia and gonorrhoea gonorrhoea only: chlamydia is not looked for in the throat. Routine among males with male partners, otherwise to be discussed with a doctor |
Swab of the lesion | Only with symptoms right away Syphilis if there is a lesion Only with symptoms right away Genital herpes () if there is a lesion, while it is still visible Only with symptoms right away Mpox if there is a lesion |
Stool test | Only with symptoms right away Gut infections with diarrhoea after oro-anal contact |
Examination | Only with symptoms right away Scabies / pubic lice diagnosed by sight with itching |
For these infections the guidelines do not provide for routine testing after sex: there is no window period to wait out, and looking for them across the board, without a reason, is not recommended. They are looked for in two cases only: if symptoms appear (sores, discharge, itching, diarrhoea…) or if a partner has been diagnosed. In both, it is the doctor who decides which test to run. | |
The next step
This page states what the guidelines indicate, not what to do: choosing the tests rests with the doctor, or with the consultation at the centre. The summary of this scenario, with its sources, downloads as a PDF to be taken there.
The summary appears once the questions on the left have an answer.
Tests for everyone.
Some tests and vaccines are not counted from an encounter and do not change with the scenario: they apply to everyone, including people who are not having sex. That is why they sit outside the table, on a page of their own.
Considered, not to be done.
We looked at them: the guidelines say not to do them, because without symptoms they do not help, or they raise false alarms. The list, with the reason for each one, sits on a page of its own.
Scientific sources.
Everything on this page comes from here: international guidelines, surveillance data, individual studies and documents on services and vaccines.
The recommendations on which tests to run, on which sample and with what timings come from here.
- CDC — Sexually Transmitted Infections Treatment Guidelines, 2021Centers for Disease Control and Prevention (United States)
- IUSTI Europe — European STI guidelinesInternational Union against Sexually Transmitted Infections, 2025 edition
- IUSTI 2025 — European guideline on the management of Chlamydia trachomatisWhite J. et al., Int J STD AIDS, 2025 · DOI 10.1177/09564624251323678
- BASHH — British Association for Sexual Health and HIV, guidelinesUnited Kingdom · includes the recommendations on M. genitalium and Ureaplasma
- BHIVA — British HIV Association, guidelinesUnited Kingdom · window periods and HIV testing
- EACS GuidelinesEuropean AIDS Clinical Society · PrEP and monitoring of people living with HIV
- USPSTF — Genital Herpes Infection: Serologic ScreeningUS Preventive Services Task Force · grade D recommendation
The data on how much the infections circulate, and in which populations.
- ECDC — Annual Epidemiological ReportEuropean Centre for Disease Prevention and Control · 2024 data, published in 2026
- ISS — Surveillance of sexually transmitted infectionsIstituto Superiore di Sanità · Notiziario ISS vol. 38 no. 7-8, 2025 · data to 31 December 2023-2024
- WHO — Sexually transmitted infections (STIs), fact sheetWorld Health Organization · updated 10 September 2025
The specific figures — window periods, prevalences, how well doxy-PEP works — come from these papers.
- CDC — Testing for Hepatitis C Virus Infection: Updated GuidanceMMWR Recomm Rep 2020;69(RR-6) · anti-HCV and HCV-RNA window periods
- CDC — Guidelines for the Use of Doxycycline Post-Exposure ProphylaxisMMWR Recomm Rep 2024;73(2) · 6 June 2024
- Natsal-3 — prevalence of Trichomonas vaginalis in the United KingdomField N. et al., Sex Transm Infect, 2018
- Extragenital transmission of gonorrhoea (kissing, rimming, saliva)Chow E.P.F. et al., J Int AIDS Soc, 2019 · Fairley mathematical models, Melbourne
- DoxyPEP trial — post-exposure doxycyclineLuetkemeyer A.F. et al., N Engl J Med, 2023
What the national health service offers, and where to get tested free and anonymously.
- Ministry of Health — STIs, HIV and vaccinationPNAIDS, national vaccine prevention plan, Mpox circulars of 5.8.2022 and 19.8.2024
- ISS — Uniti contro l’AIDS · AIDS and STI Helpline 800 861061Information, guidance to clinics, anonymity
- Community-based checkpointsMilano Check Point, BLQ Checkpoint (Bologna) and the other services run by ASA, Arcigay, LILA and NPS: free anonymous rapid testing, PrEP desks