How to test for Chlamydia: which sample you need and when

Chlamydia is tested with a urine sample or a swab. The lab uses a NAAT (nucleic acid amplification test), which looks for the genetic material of the bacteria. UK guidelines say NAATs are the standard test for Chlamydia, and they’re highly sensitive and specific.

A blood test won’t find Chlamydia. Blood tests for Chlamydia are no longer considered suitable, because NAATs are much more accurate. Read more in “Why is Chlamydia known as a silent STI?”

It depends on your body and the kind of sex you’ve had:

• Women: a vaginal swab is the best sample, and you can take it yourself. It picks up 96% to 98% of infections. Urine tests are less sensitive in women, because there are fewer bacteria in the urethra.
• Men: a first-catch urine sample, which is the first part of your pee, is as good as or better than a swab from the penis, and easier to give.
• Anal sex: a rectal swab, which you can usually take yourself.
• Oral sex: a throat swab, which you can also take yourself.

A urine test or vaginal swab only checks your genitals. If you’ve had anal or oral sex, an infection in your bottom or throat could be missed without a separate swab. UK guidelines say men who have sex with men should be tested at all three sites. For women, they don’t recommend routine throat or rectal tests, but your sexual history and any symptoms can guide which swabs you need.

Chlamydia tests are most reliable from 2 weeks after sex. If you test sooner, a negative result may need repeating. UK guidelines say to test when you first seek help and, if you had sex in the last 2 weeks, to test again 2 weeks after it.

UK guidelines also suggest testing:

• every year, and after a new partner, if you’re sexually active
• at the start of a relationship, if you then only have sex with each other
• every 3 months if you’re at higher risk, for example if you take PrEP, have had more than 10 partners in the past year or have had a bacterial STI in the past year

If you have symptoms, such as pain when you pee, unusual discharge or bleeding after sex, get tested.

Yes. With a home test kit, you take your sample in private and post it to a lab. Some Chlamydia home tests use a urine sample, and some use a swab. Home testing is now popular: in 2025, the biggest share of Chlamydia tests in women aged 15 to 24 in England, about 2 in 5, came through online services.

Follow the kit’s instructions carefully, so your sample can be tested. Read more in “How to take a urine sample for a home test”

NAAT lab tests are very accurate, but no test is 100% accurate. UK guidelines say:

• a self-taken vaginal swab picks up 96% to 98% of infections
• for men, a urine test is at least as good as a swab from the penis
• some rapid tests don’t use NAAT technology, and these are less sensitive

Testing too early, or not testing the right part of the body, can mean an infection is missed. That’s why timing and the right sample matter.

Chlamydia is treated with antibiotics. The usual treatment is doxycycline twice a day for 7 days. It isn’t suitable in pregnancy, so other antibiotics are used instead.

• Avoid sex, including oral sex, until you and any partner have finished treatment, or for 7 days if you’re given azithromycin, and your symptoms have gone.
• Tell your recent partners, so they can get tested and treated.
• If you’re under 25, UK guidelines recommend testing again 2 to 6 months after treatment.
• If you’re pregnant, you’ll be offered another test after treatment to check it has worked.

If it isn’t treated, Chlamydia can pass to a baby during birth and cause an eye or lung infection. If you test positive with Better2Know, our doctors can help you get the treatment you need.

Better2Know offers:

• Chlamydia home test: a urine test you take at home, from 14 days after sex, with results in 2 days. Our Chlamydia and Gonorrhoea home test checks the same kind of sample for Gonorrhoea too.
• Peace of Mind: tests for Chlamydia, Gonorrhoea and Syphilis from 14 days after sex, with results in 2 days. You can book it at one of our clinics or order a home test kit.
• Chlamydia and Gonorrhoea (Rectal Swab) and Chlamydia and Gonorrhoea (Throat Swab): if you’ve had anal or oral sex, from 14 days after sex, with results in 2 days.
• Oral Screen: a home test kit that checks a throat swab and a urine sample for Chlamydia and Gonorrhoea, and a finger-prick blood sample for Herpes 1, Herpes 2 and Syphilis, from 14 days after sex (28 days for Herpes), with results in 2 days.
• Full Screen: tests for 7 infections, including Chlamydia, Gonorrhoea, HIV and Syphilis, from 28 days after sex, with results in 3 days (5 days for the home test).

If you test before 45 days, a negative HIV result needs a repeat test. A Syphilis test in the first 3 months after sex can miss the infection, so you may need a repeat test. Not sure which test you need? Our Patient Care Team is available 24/7 on 020 7099 0955.

Does cervical screening test for Chlamydia?

No. Cervical screening looks for HPV, and routine blood tests don’t detect Chlamydia either. You need a separate Chlamydia test.

Do I need a test if I have no symptoms?

Yes, if you’ve had sex without a condom with a new or casual partner. Around 70% to 80% of people with Chlamydia don’t know they have it, and in women, untreated Chlamydia can cause problems such as pelvic inflammatory disease.

How soon after treatment can I test again?

Wait at least 3 weeks after finishing treatment. A NAAT can pick up genetic material from dead bacteria for a while after treatment, so testing sooner can give a positive result even though the infection has gone.

Testing for Chlamydia is simple. It uses a urine sample or a swab rather than a blood test, and you can take most samples yourself, at a clinic or at home. Test from 2 weeks after sex, and if you’ve had anal or oral sex, ask about swabs for those areas too.

Order a Chlamydia home test or book a test at a clinic near you. Our Patient Care Team is available 24/7 on 020 7099 0955.

Not in the UK? Choose your country from the selector at the top of the page for local tests and prices.

This article originally appeared on 9 November 2012 and was last updated on 1 October 2026.

This article is general information and not a substitute for personal medical advice.

Sources

1. NHS, Chlamydia, reviewed 24 October 2024. https://www.nhs.uk/conditions/chlamydia/
2. British Association for Sexual Health and HIV, UK national guideline for the management of infection with Chlamydia trachomatis, 2026. https://www.bashh.org/_userfiles/pages/files/national_guideline_for_the_management_of_infection_chlamydia_trachomatis_2026.pdf
3. British Association for Sexual Health and HIV, Summary guidance on testing for sexually transmitted infections, 2023. https://www.bashh.org/_userfiles/pages/files/resources/bashh_summary_guidance_on_stis_testing_2023.pdf
4. UK Health Security Agency, NCSP: programme overview, updated 24 June 2021. https://www.gov.uk/government/publications/ncsp-programme-overview/ncsp-programme-overview
5. UK Health Security Agency, Sexually transmitted infections and screening for chlamydia in England: 2025 report, 2 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
6. Brook, Chlamydia, updated 30 September 2026. https://www.brook.org.uk/your-life/chlamydia/
7. British HIV Association, British Association for Sexual Health and HIV and British Infection Association, Adult HIV testing guidelines, 2020. https://bhiva.org/wp-content/uploads/2024/10/HIV-testing-guidelines-2020.pdf
8. British Association for Sexual Health and HIV, UK guidelines for the management of syphilis, 2024. https://bashh.org/_userfiles/pages/files/syphilis_2024.pdf