How often should you get an STI test?

Because many STIs don’t give you any. The World Health Organization estimates that more than 1 million curable STIs are acquired every day worldwide in people aged 15 to 49, and that most of them have no symptoms. Chlamydia is a good example: the UK Health Security Agency (UKHSA) describes it as a largely asymptomatic infection.

That matches how people really use testing. In England in 2025, 70.3% of STI tests in sexual health services were done on people without symptoms. Testing when you feel fine is normal, and it is the whole point.

Think of it as two different moments: before things get serious, and after any risk.

If you or your new partner had other partners recently, a check around the time you start having sex means you both begin from known results. If something has already happened, such as a split condom or sex without one, the timing depends on the test. Start counting from the last time it happened, even if the worry only began later.

The Peace of Mind screen works from 14 days after the incident. It covers Chlamydia, Gonorrhoea and Syphilis. A Syphilis test at 14 days picks up few infections, so a negative result needs a later test to confirm it. Screens with a 28-day incubation period cover more infections in one go.

If you are not sure which of these fits, our post on how to choose the right test after a new partner walks through it. If this is your first time testing at all, what to expect from your first STI test takes the mystery out of it.

Usually the useful moments are the start of the relationship and any change after that. Once you have both tested, and neither of you has had sex with anyone else since, there is little reason to repeat it on a timer.

The picture changes if either of you has sex with someone else, or if you are not sure. Having one partner is not the same as having no risk. Among women attending sexual health services in England who reported at least one partner in the past 3 months, 60.3% of gonorrhoea diagnoses were in those who reported only one. That reflects how many attendees have one partner, so it isn’t a sign that one partner is riskier. It does show that having one partner is enough to get an infection.

If a new positive result turns up, it does not tell you who brought it in, or when. An infection can go unnoticed for a long time. If your partner won’t test or the subject is hard to raise, this post on partners who avoid testing may help you find the words.

More often than someone with one partner, and on a schedule you will actually keep. Pick a rhythm that fits your life, shorten it the more partners you have, and tie it to something you remember, like the start of each season.

UKHSA figures show where infections turn up. Among gay, bisexual and other men who have sex with men who reported at least one recent partner at English sexual health services, 81.6% of gonorrhoea diagnoses were in men with 2 or more recent partners. UKHSA notes that this broadly reflects how many partners people in that group report, so it is not a measure of risk on its own. The reasoning is simpler: each new partner is another chance for an infection to pass on unnoticed.

The kind of sex matters too. Oral sex carries risk too, and it is easy to forget. Our post on testing after unprotected oral sex explains what that looks like.

Not on its own. UKHSA records it as HIV PrEP: it is there to prevent HIV, and it is not a test, so it tells you nothing about Chlamydia, Gonorrhoea or Syphilis. If you have regular PrEP check-ins, they make a natural anchor for a full STI test.

Between those check-ins, test sooner if your number of partners suddenly goes up, if a partner tells you they have tested positive, or if you notice a symptom. Our HIV information page covers HIV testing in more detail.

• You have symptoms. Burning when you pass urine, discharge, a sore, an itch or a rash. See a doctor if they are severe or persist, and test as well.
• A partner tells you they tested positive. If you first had sex with them more than 14 days ago, test straight away. If it was less than 14 days ago, wait until day 14.
• Something went wrong. A split condom, a one-off night, a partner you did not know well.
• You have just finished treatment for Gonorrhoea. A test of cure is worth having, at least 2 weeks after treatment, to check the infection has gone and was not a resistant strain. After Chlamydia, a test of cure is not routinely needed if you took the full course and the symptoms have gone; if you want one, wait at least 3 weeks. Symptoms that last after treatment are a reason to see a doctor, not to retest early. UKHSA also notes that young adults who have had Chlamydia are more likely to get it again at some point, for reasons such as partners who have not been treated. That is why a partner needs treatment too, and why it is best to have no sex until you have both finished it.

If you think you may have been exposed to HIV within the last 72 hours, seek urgent medical care now rather than waiting for a test.

For a check that gives you a good overall picture, we suggest the Full Screen. It tests for Chlamydia, Gonorrhoea, Hepatitis B, HIV and the p24 antigen, Mycoplasma, Syphilis and Ureaplasma, using a blood sample and a urine sample. It works from 28 days after any incident you are concerned about, and results are reported within 3 working days of your sample reaching the laboratory.

If you want to go wider, the Platinum Screen also covers Hepatitis C, Herpes 1 and 2, Trichomonas and Gardnerella. If you are testing 14 days after a specific incident, the Peace of Mind screen is the quicker option, with results within 2 working days of your sample reaching the laboratory.

If anything is found, a consultation and treatment are part of the service, and everything is confidential. Our Patient Care Team is available 24/7 on 020 7099 0955. Products and availability vary between countries, so they can tell you what you can book where you live.

• UK Health Security Agency. Sexually transmitted infections and screening for chlamydia in England, 2025 report. June 2026. https://www.gov.uk/government/statistics/sexually-transmitted-infections-stis-annual-data-tables/sexually-transmitted-infections-and-screening-for-chlamydia-in-england-2025-report
• World Health Organization. Sexually transmitted infections (STIs), fact sheet. https://www.who.int/news-room/fact-sheets/detail/sexually-transmitted-infections-%28stis%29

Medical review. This article was medically reviewed by Dr Steve Chapman, a doctor with a wealth of clinical experience in the field of STIs, on 2 November 2026. Better2Know content is reviewed for clinical accuracy before publication and updated when guidance or surveillance data changes. It is general information and not a substitute for personal medical advice.