While You Have Symptoms, Ideally Within 48 Hours
A swab is most reliable when taken from a fresh blister or ulcer. As a sore begins to crust and heal, the amount of virus falls, and the test becomes less reliable. If you have a sore now, book now.

A blood test tells you whether you have been exposed at some point in your life. It does not tell you whether herpes is causing the symptoms you have now. If you have a lesion, swabbing it while it is there gives a real answer, which is why we ask you to come while symptoms are active.
Herpes is one of the few infections where when you test matters more than anything else. If you have a sore, blister or ulcer now, a swab taken from it can identify the virus directly and tell you definitively whether it is herpes and which type. That is a proper answer, and treatment can start the same day.
If the sore has healed, or you never had one, the picture is different, and we would rather be straight with you about it. The available blood test detects antibodies, meaning past exposure, but it cannot tell you where the infection is or when you acquired it. Since most UK adults carry HSV-1 from childhood cold sores, a positive result is very often just that, misread as a sexually transmitted infection. UK guidance therefore does not recommend blood testing people without symptoms, and we agree with it.
So the practical advice: if you have symptoms, come in now while they are present. If you do not, talk to us before paying for a test, because we may tell you it will not answer your question, and we would rather do that than sell you a result you cannot use.

A swab is most reliable when taken from a fresh blister or ulcer. As a sore begins to crust and heal, the amount of virus falls, and the test becomes less reliable. If you have a sore now, book now.
Talk to us first. See the section below and the section below for why a blood test may not tell you what you want to know.
Swabbing a healed area will not detect anything. Speak to a doctor about whether anything useful can be established, and be aware that the honest answer is sometimes no
Same-day slots are usually available across all ten clinics, Monday to Friday, 8 am to 7 pm, and Saturday, 9 am - 2 pm.
Step 1
Same-day slots available. The sooner after a sore appears, the more reliable the test.
Step 2
A doctor examines the area because other conditions cause genital sores too, and getting the diagnosis right matters.
Step 3
A swab is taken directly from the sore. Briefly uncomfortable and over quickly.
Step 4
Next-day results. Antiviral treatment can be started at the appointment where clinically appropriate, without waiting for the result.

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Herpes simplex virus comes in two types.
HSV-1 traditionally causes cold sores around the mouth and is extremely common, with most UK adults carrying it, usually acquired in childhood from a family member.
HSV-2 traditionally causes genital herpes. That distinction has blurred, because HSV-1 now causes a large share of first episode genital herpes, transmitted through oral sex.
Why the blood test is problematic for people without symptoms. The type specific antibody test tells you whether you have been exposed to HSV-1 or HSV-2 at some point. It cannot tell you where the virus is, or when you acquired it. So the commonest outcome of testing an asymptomatic person is a positive HSV-1 result, which for most people reflects childhood cold sores and says nothing about their sexual health, yet is very easily heard as “you have genital herpes”. False positives also occur, particularly at borderline levels. And there is no treatment for asymptomatic infection, so nothing changes as a result. Anxiety with no action available is a poor return on a test, which is why UK guidance advises against it and why we would rather talk to you first.
Why the swab is different. A swab from an active sore detects the virus itself, at that site, right now, and identifies the type. That is a real answer: it confirms the diagnosis, tells you which type you have, which helps predict how often recurrences are likely, and confirms it is herpes rather than one of the other conditions that cause genital ulcers.
What a diagnosis actually means, in perspective. Genital herpes is common, it is manageable, and it is not dangerous to an otherwise healthy adult. First episodes are usually the worst; recurrences are typically shorter and milder, and become less frequent over time. Antivirals shorten episodes, and suppressive treatment can prevent them for people with frequent recurrences. Transmission can be reduced, though not eliminated, with antivirals and by avoiding sex during an episode. The stigma attached to herpes is out of all proportion to its medical significance, and that mismatch causes more distress than the virus does.
| Private Herpes Test | NHS | |
|---|---|---|
| Access | Book directly, same day usually | Sexual health clinic, some walk in or GP |
| Results | Next day | Typically several days |
| Asymptomatic blood testing | Available, with caveats, and not recommended | Generally not offered, in line with guidance |
| Suppressive treatment for recurrences | Available | Available |
| Antiviral treatment | Prescribed, £25 plus medication | Free prescription, or standard charge |
| Swab while symptomatic | Ask at your appointment | Standard practice at sexual health clinics |
NHS sexual health clinics handle herpes well and they are free, and they will swab a sore the same way we would. Private testing is worth paying for when you want a specific appointment time or a faster result. What matters most is being seen while symptoms are present, wherever that happens.
Ideally, a swab taken from an active sore, which detects the virus directly and identifies the type. A blood test detects past exposure but cannot say where or when.
Usually not, and we will explain why. Most UK adults carry HSV-1 from childhood cold sores; the test cannot tell you where the infection is, and there is no treatment for asymptomatic infection. UK guidance advises against it.
The next day.
Antiviral tablets, which shorten an episode and are most effective when started early. For frequent recurrences, suppressive treatment taken daily can prevent them.
Transmission is possible between episodes, though less likely. Antivirals and avoiding sex during an episode both reduce the risk considerably.
Book an appointment and tell us you are pregnant. A first episode late in pregnancy has implications for delivery and needs specialist input.
A swab needs an active sore. Once it has healed, there is nothing to swab, so speak to a doctor about whether anything useful can be established.
It is an understandable question, and a conversation is more useful than a test. A positive antibody result would not tell you whether you are at risk of symptoms, and a negative one would not protect you. What helps is knowing what to look for and how to reduce transmission.
Swabbing an active sore is briefly uncomfortable. It is over quickly.
Often, at first. Recurrences are usually milder and shorter than the first episode and tend to become less frequent over time.
Not to an otherwise healthy adult. It matters more in pregnancy and for people who are immunosuppressed, both of whom need specific advice.
Yes, and this is worth an examination. Several conditions cause genital sores and ulcers, some of which need quite different treatment.
If you have a sore or blister, book today. A swab while symptoms are present gives a clear result, and treatment can start at the appointment.