Genital Herpes

Formal name: Herpes Simplex Virus (HSV)

At a Glance

Why Get Tested?

To screen for or diagnose infection with the herpes simplex virus

When to Get Tested?

If you have symptoms of an infection with the herpes simplex virus

Sample Required?

A swab or scraping from a blister or sore in the infected area

The Test Sample

What is being tested?

The test is looking for evidence of infection by the Herpes simplex virus, a common sexually transmitted disease that causes small fever blisters (vesicles) on the mouth or genitals. The blisters seen around the oral cavity and in the mouth are commonly called “cold sores” and are evidence of active herpes infection.

How is the sample collected for testing?

Your doctor will take a swab or scraping from a blister or sore in the mouth or genital area.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

The Test

How is it used?

The test is used in two ways:

to detect the presence of the herpes simplex virus, and
to screen sexually active people.

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When is it requested?

Your doctor may use the test if you have a blister or vesicle on your genitals or mouth. Any sore in the genital area can be a symptom of a serious disease and should be tested.

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What does the test result mean?

A positive culture test on a scraping from a vesicle indicates an active infection.

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Is there anything else I should know?

There are two types of herpes simplex virus (HSV):

HSV-1 typically causes fever blisters or cold sores on the mouth or face, which is called oral herpes.
HSV-2 typically causes vesicles in the genital area and is called genital herpes.

The type of infection depends on the location of the virus more than on the type of virus—each type can cause either genital or oral infections if that is where it is contracted.

Blood tests are available to diagnose a herpes infection; however, they are not completely reliable for differentiating between HSV1 and HSV2. Most doctors rely on visual inspection of any lesions and culture of the scrapings taken from the infected area. Once the virus is grown in culture, the herpes virus can be typed using specific antisera for HSV 1 and HSV 2.

Herpes can make people more susceptible to HIV infection and can make people who have HIV more infectious to others.

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Common Questions

1. How is herpes transmitted?

HSVs are transmitted through direct contact, which can include kissing; vaginal, oral, or anal sex; or other skin-to-skin contact. Genital herpes is most easily contracted by having sex with someone who has a vesicle, but it can be transmitted even if there are no sores or other symptoms. People often catch it by having sex with someone who doesn't know they are infected.

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2. What are the symptoms of herpes?

Many people who have herpes don’t know it because they never have symptoms or don’t recognize the symptoms they do have. When you are first infected, you may have obvious and painful lesions at the site of infection. These lesions appear within two weeks after the is transmitted and usually heal within two to four weeks. The vesicles can appear in the vaginal area, on the penis, around the anus, or on the buttocks or thighs. This primary episode can include a second outbreak of lesions and even flu-like symptoms of fever and swollen glands. However, you may not have any lesions or have symptoms that are so mild that you don’t notice them or mistake them for something else, such as insect bites or a rash.

After the primary episode, the virus goes into an inactive state within your body. It may cause outbreaks from time to time. The outbreaks, which last about a week, can be blisters or open sores that crust over and then disappear. Sometimes, the virus can become active and infectious with no noticeable sores. The virus never goes away, and the frequency and severity of these recurrent episodes vary greatly among individuals.

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3. How is it treated?

There is no cure for herpes. Some drugs can reduce the frequency and shorten the length of outbreaks. The most effective drug currently available is aciclovir. It stops the virus from reproducing by interfering with its DNA.

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4. How common is it?

Seventy percent of UK adults have oral herpes. About 10 percent of adults have genital herpes, but up to two-thirds of them don't know because their symptoms are so mild.

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5. How can herpes be prevented?

See the Herpes Viruses Association website from the Related Pages section.

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.