When can you test for Chlamydia? Timing your test for an accurate result

Chlamydia is a bacterial infection passed on through vaginal, anal and oral sex, and by sharing sex toys. It is the most commonly diagnosed sexually transmitted infection (STI) in England.

It is often called a silent STI, because it usually causes no symptoms at all. Left untreated, it can lead to pelvic inflammatory disease, pain and swelling in the testicles, and problems with fertility. The good news is that it is simple to test for and straightforward to treat with a short course of antibiotics.

Fourteen days after the sexual contact you are worried about. This is the window period for every Better2Know Chlamydia test: the number of days that need to pass before the test can reliably detect the infection.

• From then on: a negative result from a laboratory (PCR) test is one you can rely on, and you can stop worrying about Chlamydia from that encounter.
• Before then: a positive result is accurate, but a negative one is not yet conclusive.
• If you have symptoms, or a partner has tested positive and you first had sex with them more than 14 days ago: you don’t need to wait. Book a test as soon as you can, and tell us when you book.

After sex with someone who has Chlamydia, the bacteria settle in the urethra, the cervix, the throat or the rectum and start to multiply. A Chlamydia test looks for their genetic material in a urine sample or a swab, and in the first few days there may simply not be enough bacteria for it to find.

Count the 14 days from the most recent time you were at risk, not from the day you started to worry. If there were several occasions, the clock starts at the last one.

You can, and we understand why people want to. Two weeks can feel like a very long time.

Here is what an early test can and can’t do. If it comes back positive, that result is accurate, and it means treatment can start sooner. If it comes back negative, it can’t yet rule the infection out, so book a second test for 14 days after the encounter. That second result is the one that counts.

One more thing worth knowing: leftover antibiotics are best avoided while you wait. A partial course can suppress the infection without clearing it, and it can make a later result harder to interpret.

Most people with Chlamydia have no symptoms. The UK Health Security Agency estimates that around 70% to 80% of people with Chlamydia are unaware they have it. When symptoms do appear, often two to six weeks after infection and sometimes much later, they look different in men and women.

Symptoms in men

Men may notice a burning feeling when passing urine, a white, cloudy or watery discharge from the tip of the penis, or pain and swelling in the testicles. Our guide to what Chlamydia discharge looks and smells like describes another common sign.

Symptoms in women

Women may notice a burning feeling when passing urine, a change in vaginal discharge, bleeding after sex or between periods, or pain low in the abdomen.

Symptoms in the throat and rectum

Chlamydia in the throat or rectum is usually silent, and a urine sample does not test either site. If you have given oral sex or received anal sex, add a throat or rectal swab to your test. Our guide to testing after unprotected oral sex explains why.

Whatever the symptom, it is a reason to test now rather than wait for the window period to pass.

• Note the date 14 days after your last risk, so there is nothing to remember.
• Condoms, or a break from sex, protect a partner until you have your result. If you have Chlamydia, you can pass it on during the window period even though you feel fine.
• Think about what else you want checked. HIV and Hepatitis B have a 28-day window period, so a second screen at 28 days covers them. You can book both appointments at the same time.

Our data shows that 61% of people who test for Chlamydia at our UK clinics do so as part of a wider sexual health screen. The same encounter can expose you to Gonorrhoea and Syphilis as well, and from 14 days our Peace of Mind screen checks all three in one visit or one home test kit. Syphilis can take longer to show up, so a negative Syphilis result at 14 days needs a follow-up test later on, and our team can tell you when.

You can test at one of our private clinics across the UK, where most appointments take around 10 to 15 minutes and many are available the same or next day, or order a home test kit, which arrives in plain packaging with free return postage.

If you need an answer today, our instant test for Chlamydia and Gonorrhoea gives a result in the clinic in under 30 minutes. It is less sensitive than a laboratory (PCR) test, especially if you have no symptoms, so a negative result is best confirmed with a laboratory test.

Results are reported to your secure online patient area within two working days of your sample reaching the laboratory. If anything is found, we can arrange a doctor’s consultation and help you get treatment. Everything is confidential and anonymous, and our Patient Care Team is available 24/7 on 020 7099 0955 if you want to talk it through first.

Can I test for Chlamydia and Gonorrhoea at the same time?

Yes. Both are tested from the same urine sample or swab, and both have a 14-day window period. Chlamydia is usually silent and Gonorrhoea can be, so testing for one without the other leaves a gap.

Can I take a Chlamydia test during my period?

Yes. You can give a urine sample at any time of the month, and a vaginal swab can be taken too. If bleeding is heavy, you may prefer a lighter day. See our post on testing for STIs during your period.

Fourteen days after the sexual contact you are worried about is when a Chlamydia test gives you an answer you can rely on. Before then, a test can find an infection but can’t rule one out. Symptoms mean you can test today, and so does a partner’s diagnosis if you first had sex with them more than 14 days ago.

Whatever your situation, there is a next step. Take control of your sexual health and book a confidential Chlamydia test with Better2Know, online or by phone.

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 15 October 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.