What is a herpes (HSV) test?

Herpes is a common viral infection caused by the herpes simplex virus (HSV). Most people with HSV don't have any symptoms. But HSV can cause painful blisters or sores on the affected parts of the body. HSV mostly affects the mouth (oral herpes) and the vagina or penis (genital herpes), but it can also affect the eyes and other parts of the skin.

HSV tests look for signs of the herpes simplex virus usually in a sample of your blood or fluid from a sore. There are two main types of HSV, and testing can tell which type you have:

• HSV-1 usually causes oral herpes, which can result in cold sores ("fever blisters") on or around your mouth. Most people get oral herpes by the time they're young adults. It's usually spread by non-sexual contact with saliva (spit) from a person who has an HSV-1 infection. That may happen if you share forks, cups, or towels. HSV-1 can also cause genital herpes. This may happen if you receive oral sex from a partner with a cold sore.
• HSV-2 is the most common cause of genital herpes. Genital herpes is a sexually transmitted disease (STD). That means you get it through sexual contact with a person who has a herpes infection. You can catch genital herpes from someone even if they don't have symptoms. HSV-2 can also spread to the mouth, causing oral herpes. This may happen if you give oral sex to a person who has genital herpes from HSV-2.

HSV infections are likely to clear up and come back in the future, but outbreaks tend to be milder and less frequent over time. Repeat outbreaks happen more often with HSV-2 than with HSV-1. So, testing to find out which type you have helps you know what to expect.

There are a few types of HSV tests:

• A swab test takes a sample of fluid from a sore, which may be used to do:
  • A viral culture. For this test, cells from your sample are grown in a lab and then checked for HSV.
  • A polymerase chain reaction (PCR) test. This test looks for genetic material from HSV in your sample.
• A blood test looks for HSV antibodies in a blood sample. HSV antibodies are proteins that your immune system makes fight the virus. Your body makes different antibodies for HSV-1 and HSV-2. This test can be done when you don't have sores.

There is no cure for HSV, but medicines can help manage outbreaks. HSV usually doesn't cause any major health problems. But if you're pregnant and have genital herpes, you can pass the virus to your child. This can lead to a life-threatening HSV infection for your baby. In rare cases, HSV can infect your brain and spinal cord, causing serious illness.

Other names: herpes culture, herpes simplex viral culture, HSV-1 antibodies, HSV-2 antibodies, HSV DNA

What is it used for?

An HSV test may be used to:

• Find out whether sores on your mouth or genitals are caused by HSV and, if so, which type
• Check for an HSV infection if you've had a high risk of exposure to the virus
• Check for an HSV infection in a baby born to a person who has HSV

Why do I need an HSV test?

You may need an HSV test if:

• You have symptoms of herpes. Symptoms of a first HSV infection may include:
  • Blisters or sores on the mouth, genitals, anus, buttocks, or other areas of skin. The sores develop a crust as they begin to heal.
  • Fever and flu-like symptoms.
  • Swollen glands.
  • Pain or tingling in the affected area.
• Your partner has genital herpes or symptoms that might be genital herpes

In general, medical experts don't recommend HSV testing for people without symptoms of HSV. If you are being tested for other STDs, your health care provider may choose to include an HSV test based on your risk of exposure. Ask your provider if you should be tested.

In rare cases, HSV can infect the brain and spinal cord, leading to encephalitis or meningitis. You may need an HSV test if you have one of these serious conditions.

What happens during an HSV test?

There are several different types of tests for HSV that use different samples:

• For a swab test, a health care professional will use a swab to collect fluid and cells from a herpes sore that has not begun to heal yet.
• For a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

At-home tests are available for HSV. These tests usually use a sample of blood that you collect at home and send to a lab. Talk with your provider to find out if at-home testing is right for you.

If your provider thinks you have an HSV infection in your spinal cord or brain, you may have a test of your cerebrospinal fluid (CSF) to look for signs of the virus. CSF is a fluid that flows in and around your brain and spinal cord. A thin needle is inserted into your spine to remove a small amount of CSF. This procedure is called a lumbar puncture or spinal tap.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a swab test or a blood test. For a lumbar puncture, you may be asked to empty your bladder (pee) and bowels (poop) before the test.

Are there any risks to the test?

After a swab test, but you may have a little bit of bleeding or discomfort where your skin was swabbed. This usually doesn't last long.

A blood test has very little risk. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

If you have a lumbar puncture, you may feel some pain or tenderness in your back where the needle was inserted. You may also have some bleeding at the site or a headache.

What do the results mean?

The meaning of your test results depends on the type of HSV test you had. To understand your results, your provider will consider your health history and any symptoms you have.

In general:

• Negative/Normal test results mean that signs of the herpes virus were not found in your sample and you are unlikely to have an HSV infection. If you had a blood test for HSV antibodies, it's important to know that you can have a negative result when you really do have a herpes infection. That's because your body takes up to three months to make HSV antibodies. If you had a blood test too soon after an infection began, your test result may not show any antibodies.
• Positive/Abnormal test results mean that signs of HSV were found in your sample. If you had a blood test that showed you have HSV antibodies, the antibodies could be from an active infection now or a past infection.

If you have HSV, treatment can help reduce the number of outbreaks and control your symptoms. It's important to know that having an HSV infection may increase your risk of getting HIV and other STDs. So, talk with your provider about HIV testing along with other STDs.

It's also important to take steps to avoid spreading HSV to others. Using condoms can help. Since outbreaks come and go, ask your provider how to know when your risk for spreading the herpes virus may be high.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about an HSV test?

The best way to prevent genital herpes or another STD is not to have sex. If you are sexually active, you can reduce your risk of infection by:

• Having sex with only one person who has sex only with you (mutual monogamy) after both of you are tested for STDs.
• Using condoms correctly every time you have sex.