Can you get tested for Herpes without an outbreak?

Yes. A blood test looks for antibodies to Herpes, which your body makes after an infection, so it doesn’t need a sore or blister. A swab test, the main test for Herpes, can only be done when you have a sore to swab.

But testing for Herpes without symptoms isn’t routine in the UK. UK guidelines don’t recommend it for most people, and Herpes isn’t part of a standard sexual health screen. A blood test has real limits, and finding Herpes in someone without symptoms hasn’t been shown to stop it spreading.

A blood test can show you’ve had Herpes at some point, but not where or when.

Herpes is very common, and most people who have it don’t know. Only about 1 in 3 people with Herpes know they have it, because many never get symptoms, or have symptoms so mild they don’t notice them.

When symptoms do appear, they usually start 2 to 12 days after infection, but some people get their first outbreak months or even years later. So a first outbreak doesn’t always mean you caught Herpes recently.

Herpes can be passed on even when there are no symptoms. The risk is highest in the first 6 months after infection and becomes rare after 2 years.

A Herpes blood test looks for IgG antibodies to Herpes 1 (HSV-1) and Herpes 2 (HSV-2). A positive result means you’ve been infected at some point, and what it means depends on the type:

• a positive HSV-2 result usually means a genital or anal infection, as HSV-2 is almost always caught through sex
• a positive HSV-1 result could be from a cold sore infection you caught as a child, or from a genital infection, and the test can’t tell which

The test also has limits:

• antibodies take time to appear, so a test soon after sex can miss a new infection
• a weak positive result can be a false positive, especially in people at low risk of Herpes
• up to 12% of people with Herpes lose their antibodies over time, so a negative result doesn’t always rule it out

A blood test can’t tell you when you caught Herpes, or who from. Read more in “How accurate are blood tests for Herpes?”

UK guidelines say a blood test can be useful in a few situations:

• your partner has genital Herpes and you’ve never had symptoms, to find out whether you already have the same type, especially if you’re planning a pregnancy
• you keep getting sores, but swab tests have been negative
• you’ve just had a first outbreak confirmed by a swab, to tell a new infection from one you’ve had for a while, which matters most late in pregnancy

If your partner has Herpes and either of you is pregnant, or you’re planning a pregnancy, tell your midwife or doctor. You may be advised to avoid sex late in pregnancy, and the partner with Herpes may be offered daily antiviral tablets.

If you only want reassurance, a blood test may not give you a clear answer.

If you have a sore, blister or ulcer, a swab from it is the best test. It looks for the virus itself, and it shows whether you have Herpes 1 or Herpes 2. UK guidelines say Herpes should be confirmed with a test like this, because it doesn’t always look the way people expect.

Get the swab done as soon as you can, while the sore is fresh. 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 always rule Herpes out.

If a sore appears, get it tested straight away. Read more in “Swab, blood or urine: which Herpes test should you choose?”

If you’ve had sex with someone who has Herpes, or you’re worried you might have caught it:

• watch for tingling, itching or small blisters around your genitals, anus, thighs or bottom
• if a sore appears, get a swab test as soon as you can, and don’t put any cream on it first
• avoid sex, including oral sex, while you have any symptoms

Treatment for a first outbreak works best if it’s started within 5 days of the symptoms appearing.

It’s worth testing for other STIs too. Chlamydia and Gonorrhoea tests can be taken from 2 weeks after sex, and a lab HIV test is reliable from 45 days.

There’s no cure for Herpes, but outbreaks usually become milder and less frequent over time, and some people never have another one. Treatment depends on how often you get symptoms:

• a short course of antiviral tablets, started as soon as symptoms appear, can shorten an outbreak by 1 or 2 days
• daily tablets can reduce how often outbreaks happen, and lower the chance of passing Herpes to a partner

Telling your partners, using condoms and avoiding sex during symptoms all lower the risk of passing Herpes on, and using these together works best.

Most people with Herpes find that outbreaks don’t happen very often. Read more in “Oral vs genital Herpes: what’s the difference?”

Better2Know offers:

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

Antibodies can take several weeks or more to show up, so a negative blood test soon after sex may need repeating. Not sure which test you need? Our Patient Care Team is available 24/7 on 020 7099 0955.

Can a blood test tell if Herpes is oral or genital?

No. A blood test can’t show where on your body the infection is. A positive HSV-2 result usually means a genital infection, but HSV-1 can be oral or genital.

Should I have a Herpes test before a new relationship?

It isn’t usually recommended if neither of you has symptoms, and Herpes isn’t part of a standard STI screen. Testing for other STIs at the start of a relationship is a good idea. If your new partner has genital Herpes, a blood test can help you both understand the risk. Read more in “New relationship? Get tested together before you stop using condoms”

Can I pass Herpes on if I’ve never had symptoms?

Yes. Herpes can be passed on when there are no symptoms, and this is an important way it spreads. The risk is highest in the first months after infection.

You can get tested for Herpes without an outbreak, but a blood test has limits, and UK guidelines only recommend it in a few situations, such as when a partner has genital Herpes. If you get a sore, a swab test is the best way to find out what it is.

Book a Herpes blood test at a clinic near you, or a Herpes swab test if you have a sore. 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 10 April 2026 and was last updated on 1 October 2026.

Medical review. This article was medically reviewed by Dr Steve Chapman, Doctor with a wealth of clinical experience in the field of STIs, on 13 July 2026. It is general information and not a substitute for personal medical advice.

Sources

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