Test Quick Guide

Genital and oral herpes are infections caused by the herpes simplex virus (HSV). HSV is spread through close contact with a person actively shedding the virus, usually through skin-to-skin or sexual contact. Even without symptoms of HSV, you can still actively shed the virus and infect others.

Lab tests diagnose HSV and confirm the type of virus causing an infection. Diagnostic tests may require a blood sample or a sample of fluid taken from a sore. Less commonly, a lumbar puncture may be used to diagnose an infection in the brain or spinal cord.

About the Test

Purpose of the test

The purpose of testing for genital and oral herpes is to identify evidence of an HSV infection. Testing for genital and oral herpes may be ordered for several reasons, including:

  • Confirming a diagnosis of HSV infection in symptomatic patients
  • Diagnosing patients with a history of genital sores who don’t have symptoms
  • Identifying a potential HSV infection in pregnant women without symptoms
  • Understanding if a sexual partner of a person with HSV is susceptible to infection
  • Estimating the frequency of future symptom outbreaks

Testing can also determine the type of HSV causing an infection. There are two main types of HSV:

  • Herpes simplex virus type 1 (HSV-1): HSV-1 is the cause of most cases of oral herpes and is often contracted during childhood. HSV-1 can also be spread to the genitals during oral sex.
  • Herpes simplex virus type 2 (HSV-2): HSV-2 is the most common cause of genital herpes. HSV-2 can also be spread to the mouth during oral sex, causing infections of the mouth or lips. HSV-2 is typically spread through sexual contact, including vaginal, oral, or anal sex.

What does the test measure?

Testing for genital and oral herpes detects evidence of an HSV infection. There are four types of tests that confirm the presence of an HSV-1 or HSV-2 infection:

  • Viral culture: A herpes viral culture is used to determine if a skin sore is infected with HSV-1 or HSV-2 by collecting a sample from a skin sore, placing it in a special laboratory environment, and watching to see if the virus or virus-related substances grow. A viral culture is most useful early in an outbreak when a sore is open.
  • Polymerase chain reaction (PCR) testing: PCR testing, also called a viral DNA test or HSV DNA test, uses a sample taken from your sore to look for the DNA of HSV-1 and HSV-2. A PCR blood test for herpes can distinguish between HSV-1 and HSV-2 infections, making this test useful in determining which virus is causing a person’s infection. PCR testing is the primary method of testing samples of cerebrospinal fluid.
  • Tzanck smear: The Tzanck smear uses a sample of cells scraped from your sore to look for cells characteristic of a herpes infection. During a Tzanck smear, cells can be examined under a microscope in a clinic or doctor’s office without needing to send the sample to a laboratory.
  • Antibody tests: Antibodies to viral antigens are produced by the immune system in response to an HSV infection. Because every type of antibody is unique to a specific antigen, herpes simplex antibody testing can determine if you are infected with HSV-1 or HSV-2. HSV antibodies can be detected in a blood sample or a sample taken from your sore. It takes time for the body to develop antibodies, so a positive result may not occur for up to three months after the initial infection.

When should I get a genital or oral herpes test?

Testing for the viruses that cause genital and oral herpes may be ordered if you have signs and symptoms of a herpes infection. Although many people who contract HSV never notice symptoms, signs of an initial infection appear 2 to 20 days after infection and depend on the type of HSV causing the infection.

When signs and symptoms of an initial infection occur, they may include:

  • Small sores on the skin
  • Blisters on the lips, penis, vagina, buttocks, anus, or around the mouth.
  • Tingling, itching, or burning on the skin
  • Fever, headache, or body aches
  • Swollen lymph nodes

After the initial infection, HSV remains dormant inside the body. HSV can reactivate throughout your life, causing symptoms of genital or oral herpes to reappear. While the trigger for an HSV outbreak is often unknown, potential triggers include fever, stress, physical trauma, and a suppressed immune system.

Generally, expert organizations do not recommend herpes testing for patients without symptoms. An exception may be made for certain patients, including:

  • Patients who have a partner with genital herpes
  • Patients seeking a more complete STD test panel, including people with multiple sexual partners
  • Babies born to a mother who has HSV

Finding a Genital or Oral Herpes Test

How to get tested

Tests for genital and oral herpes are available at doctor’s offices, medical clinics, and community-based organizations that offer STD testing. Testing is often ordered by a doctor but may be available over the counter and at community-based organizations without a physician’s orders.

Can I take the test at home?

At-home tests are available to test for evidence of an HSV infection. At-home herpes testing typically detects HSV antibodies in a self-collected blood sample and may require additional follow-up if preliminary results are positive. At-home herpes tests can be obtained online or at a local pharmacy.

How much does the test cost?

The cost of testing for genital and oral herpes depends on the type of test that is performed, where the test is conducted, and whether you have medical insurance. Testing is often covered by insurance when ordered by a doctor, although you may still be responsible for costs such as copays and deductibles.

Taking a Genital or Oral Herpes Test

Testing for genital and oral herpes may be performed with a blood sample or a sample of fluid swabbed or scraped from a sore. Both types of samples are collected by a health professional when conducted at a doctor’s office, clinic, or community organization.

If you are experiencing an outbreak, a doctor can collect a sample for testing by swabbing or scraping a sore. Material from the sore can be used for a herpes viral culture, PCR testing, a Tzanck smear, or an antibody test.

If you are not currently experiencing an outbreak, a blood test may be used to identify HSV antibodies. If a doctor suspects a brain infection with HSV, a lumbar puncture may be performed to obtain a sample of cerebrospinal fluid for analysis.

Before the test

Before taking a test for genital and oral herpes, talk to your doctor about any medications or supplements being taken. For tests that require a sample taken from a sore, the sample must be collected when lesions are open before they begin to form a scab. For a blood test, no special preparation is required.

During the test

Collecting material from a sore may involve rubbing a sterile swab against the skin lesion or scraping the base with a scalpel.

A blood sample for antibody testing is collected intravenously or with a finger prick.

After the test

After material is collected from a skin lesion, there are no special post-test restrictions. You may have some slight bleeding or temporary discomfort where the skin was swabbed or scraped.

After your blood is drawn, slight soreness or bruising can occur but typically isn’t long-lasting. You can return to normal activities after a blood draw.

Genital and Oral Herpes Test Results

Receiving test results

Results from genital and oral herpes testing are usually available within a few business days, depending on the type of test performed. Viral culture testing may take several additional days, while rapid blood tests may be completed in as little as 15 minutes. At-home tests must be mailed to the laboratory but usually are processed within a few business days.

When going to an office or clinic, the health care team that conducted the test typically contacts you to provide results. Test reports may also be sent electronically or by mail. At-home test results are also typically sent electronically or by mail. At-home kits purchased through Health Testing Centers can be accessed through you’s online portal on the site.

Interpreting test results

The results of genital and oral herpes testing are often given as negative/normal or positive/abnormal. The interpretation of these results depends on the type of test conducted.

Viral culture and PCR test results indicate whether the sample used for the test contained HSV. A positive result means that you have an HSV infection. You may be experiencing an initial or recurrent outbreak. Test results may also include the type of HSV identified in the sample.

A negative result on a viral culture or PCR test indicates that the test sample did not contain HSV. It’s important to keep in mind that a negative viral culture or PCR test does not always mean that you don’t have a current or past HSV infection.

The results of an antibody test report whether antibodies produced in response to an HSV infection were detected in the sample used for testing. A positive result indicates that HSV antibodies were detected and you had an active outbreak or past infection.

Negative results from antibody testing indicate that HSV antibodies weren’t detected in the sample. This result could occur because you don’t have an active outbreak or past infection. A negative result can also occur because the test sample didn’t have enough of the virus to be found during testing due to a very recent infection. It can take up to three months after infection to test positive for HSV antibodies.

Using a Tzanck smear, results indicate whether or not certain cells were detected under a microscope. These cells are characteristic of a herpes infection, so positive test results suggest you have an infection. A Tzanck smear cannot distinguish between types of herpes infections, so you may have HSV-1, HSV-2, or another type of herpes virus.

Negative results from a Tzanck smear indicate that multinucleated giant cells were not found in the test sample. A negative result often isn’t helpful, as a Tzanck smear typically isn’t able to accurately identify patients who don’t have HSV or distinguish between types of herpes viruses.



See More

Ask a Laboratory Scientist

Ask A Laboratory Scientist

This form enables patients to ask specific questions about lab tests. Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, American Society for Clinical Laboratory Science. Please allow 2-3 business days for an email response from one of the volunteers on the Consumer Information Response Team.

Send Us Your Question