Swab, blood or urine: which Herpes test should you choose?

It depends on whether you have symptoms:

• If you have a sore, blister or ulcer, a swab from the sore is the best test. UK guidelines recommend it as the preferred way to diagnose genital Herpes.
• If you have no symptoms, a blood test can show whether you’ve been infected at some point, but it has limits.

All Better2Know Herpes tests check for both types of the virus, Herpes 1 (HSV-1) and Herpes 2 (HSV-2).

There are two types of Herpes simplex virus:

• HSV-1 is the usual cause of cold sores around the mouth, and is now the most common cause of genital Herpes in the UK.
• HSV-2 used to be the most common cause of genital Herpes, and is more likely to cause outbreaks that keep coming back.

Both types can infect the genitals and the skin around the anus. Oral sex can pass Herpes from the mouth to the genitals, or from the genitals to the mouth. UK guidelines say everyone newly diagnosed with genital Herpes should be told which type they have, as the type affects how likely outbreaks are to come back.

A swab test uses a small cotton bud to take fluid from a blister or sore. In the lab, swabs are usually tested with a nucleic acid amplification test (NAAT), which looks for the virus’s genetic material. PCR is one type of NAAT.

• You need a visible sore or blister for a swab test.
• Test as soon as you can. A swab from a sore that has dried or started to heal is less likely to find the virus, so a negative result then doesn’t rule Herpes out.
• Don’t put creams on the sore before the test, as they can affect the result.

A positive swab also shows which type of Herpes you have. If your sores keep coming back but swabs are negative, a blood test can sometimes help.

A Herpes blood test looks for IgG antibodies, which your body makes after infection. It can show whether you’ve had Herpes 1, Herpes 2 or both at some point, even if you’ve never noticed symptoms. Many people with Herpes have such mild symptoms that they never know they have it.

But blood tests have limits:

• Antibodies take time to build up, so a test soon after a risk can miss a new infection. You may need to repeat it 12 weeks after a possible exposure.
• A result can’t show where on the body the infection is. A positive Herpes 1 result could come from a cold sore you caught years ago.
• A low positive result can sometimes be a false positive, especially in people at low risk.

UK guidelines see blood tests as useful in certain situations, rather than as a routine check for people without symptoms. If you test positive, our doctors can explain what your result means. Read more in “How accurate are blood tests for Herpes?”

Better2Know also offers a Herpes urine test for people with symptoms, with results in 5 days. Herpes 1 and Herpes 2 are also part of the Comfort Screen, which tests a single urine sample for 8 infections and is designed for people with discomfort or unusual discharge.

UK guidelines recommend testing a swab taken from the sore itself, and don’t include urine testing for Herpes. So if you have a sore or blister you can see, a swab test is the better choice.

When to test depends on whether you have symptoms:

• If you have symptoms, get a swab test as soon as possible, while the sore is fresh.
• If you have no symptoms, a blood test can be taken from 28 days after a possible exposure, but you may need to repeat it later.

Most people who catch Herpes get no symptoms, or symptoms so mild they don’t notice. When symptoms do appear, they usually start 2 to 12 days after infection, but some people get their first sores months or even years later. So a first outbreak doesn’t always mean you caught Herpes recently. Read more in “What is the best time to get tested for Herpes?”

A positive result tells you that you have Herpes, but no test can tell you how long you’ve had it or who you got it from. A blood test also can’t show whether the infection is around your mouth or your genitals.

This matters if you’re wondering where it came from. Most people catch Herpes from someone who doesn’t know they have it, so a diagnosis isn’t proof that a partner has been unfaithful.

If your partner has never had symptoms, they don’t need a Herpes test as a matter of routine. UK guidelines say a blood test can help in some cases, for example to check whether a partner already has the same type, which can ease worries about passing it on. The result needs careful interpretation.

If either of you is pregnant, or you’re planning a pregnancy, tell your midwife or doctor that one of you has, or might have, Herpes.

Better2Know offers:

• Herpes Simplex Type 1 and 2 (Swab): if you have a sore or blister, it tests a swab from the sore for Herpes 1 and Herpes 2, with results in 5 days. You can book it at one of our clinics or order it as a home test kit.
• Blemish Screen: if you’re not sure what a sore, blister or lump is, it tests a swab for Herpes 1, Herpes 2, HPV and Syphilis, with results in 5 days.
• Herpes Simplex Type 1 and 2 (IgG): a blood test for antibodies to Herpes 1 and 2, from 28 days after possible exposure, with results in 2 days. It’s also available as a home test kit.

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.

Can you test for Herpes without an outbreak?

Yes. A blood test can show whether you’ve been infected, even if you’ve never had symptoms. It can miss a recent infection and can’t show where the infection is. Read more in “Can you get tested for Herpes without an outbreak?”

Do standard STI screens include Herpes?

Not always. The Full Screen and Peace of Mind don’t include Herpes, but you can add it. The Platinum Screen includes Herpes 1 and Herpes 2.

Can a Herpes test show who gave it to me?

No. A test can show that you have Herpes and which type, but not when you caught it or who from.

The right Herpes test depends on whether you have symptoms. If you have a sore, a swab taken as soon as possible is the best test, and it shows which type you have. If you don’t, a blood test can show a past infection, but it has limits, so it helps to talk the result through with a doctor.

Book a Herpes Simplex Type 1 and 2 (Swab) test at a clinic near you or order a home test kit. 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 2 October 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, Genital herpes, reviewed 27 June 2023. https://www.nhs.uk/conditions/genital-herpes/
2. NHS, Cold sores, reviewed 19 February 2024. https://www.nhs.uk/conditions/cold-sores/
3. British Association for Sexual Health and HIV, UK national guideline for the management of anogenital herpes, 2024. https://www.bashh.org/_userfiles/pages/files/pateletal2024britishassociationofsexualhealthandhivuknationalguidelineforthemanagementofanogenital.pdf
4. British Association for Sexual Health and HIV, Genital herpes (patient information leaflet), February 2026. https://www.bashh.org/resources/157/genital_herpes_pil
5. NHS inform, Genital herpes. https://www.nhsinform.scot/illnesses-and-conditions/sexual-and-reproductive/genital-herpes/
6. Brook, Genital herpes, accessed 1 October 2026. https://www.brook.org.uk/your-life/genital-herpes/
7. Herpes Viruses Association, Getting diagnosed with genital herpes, July 2026. https://herpes.org.uk/frequently-asked-questions/getting-diagnosed-genital-herpes/
8. Herpes Viruses Association, Antibody test for herpes, reviewed 21 July 2026. https://herpes.org.uk/frequently-asked-questions/antibody-tests-for-herpes/
9. Herpes Viruses Association, How can herpes be transmitted?, accessed 1 October 2026. https://herpes.org.uk/frequently-asked-questions/passing-transmitting-herpes/
10. Centers for Disease Control and Prevention, Genital herpes, STI treatment guidelines, 2021. https://www.cdc.gov/std/treatment-guidelines/herpes.htm