Reviewed By: Dr. Kurt Kloss, MD
Last Reviewed Date: Sep 22, 2017
Last Modified Date: Sep 22, 2017
Published Date: Jul 29, 2017
Tests for Diagnosing Herpes
Herpes infections are characterized by the appearance of sores and/or blisters on the skin in infected areas. While there are several forms of herpes, the most commonly diagnosed are oral herpes, which appears as mouth sores, and genital herpes, which manifests as genital sores. According to Johns Hopkins Medicine, as many as 50 to 80 percent of U.S. adults have oral herpes, and Centers for Disease Control and Prevention (CDC) statistics show that more than 1 of every 6 people in the U.S. between the ages of 14 and 49 has genital herpes. Both forms can be detected with a herpes test.
What causes herpes?
Herpes is caused by a virus that is passed from person to person. The typical case of oral herpes is caused by the Herpes Simplex Type 1 virus (HSV-1). Genital herpes is most often caused by the Herpes Simplex 2 virus (HSV-2). However, in recent years, a growing number of cases of genital herpes have been found to be caused by HSV-1.
Detects antibodies to the virus that causes genital herpes
How can you get herpes?
Oral herpes is spread by infected individuals, most often during an active outbreak – when that person has a herpes sore. These sores typically appear on or near the lips, and are commonly referred to as cold sores or fever blisters. When a blister or open sore is present, the virus can be transmitted via the saliva or by direct contact with a herpes sore. This frequently happens by simply kissing or hugging an infected person who has active sores. The best means of preventing infection is to avoid direct physical contact with people who have sores on the face or mouth.
Genital herpes is also spread person to person. However, this type of herpes is a sexually transmitted disease, which means you can get it by having vaginal, anal or oral sex with someone who has the disease. It can be spread most easily during outbreaks – when sores containing the virus are present in the genital area – but is also commonly spread through the skin when no symptoms are present – generally during the week before an outbreak or the week after sores have cleared away. Correct and consistent use of condoms during sex can reduce risk of contracting genital herpes, but cannot eliminate risk entirely.
What are the symptoms?
Many people who have been infected with oral herpes do not have symptoms at all. Others may have very mild symptoms after initial infection, most often the appearance of a blister in or near the mouth, which will eventually burst to form an open sore. Some may have more prominent symptoms, with numerous sores appearing inside and around the mouth and severe flu-like symptoms, including headaches and swollen lymph nodes.
The HSV-1 virus remains in the body for a lifetime after that initial infection, lying dormant in nerve cells. For some people, it will remain dormant, never causing another outbreak. For others, oral herpes sores will appear periodically, although recurring infections typically come with milder symptoms than the initial outbreaks. Generally, skin on the lips or under the nose will become red, swollen and or itchy, then painful blisters will emerge. The blisters will leak fluid and become open sores, then begin to heal after four to six days.
Infection with genital herpes also frequently comes without symptoms or very with very mild ones that often go unnoticed. For this reason, many people remain unaware that they are infected and contagious. People that do experience clear symptoms will typically develop those symptoms within a few weeks of being infected in the form of an initial herpes outbreak. Typically, this appears as blisters on the genitals, thighs and/or buttocks. Other possible symptoms include:
- Blisters in the mouth or on the lips
- Joint pain
- Difficult or painful urination
As with oral herpes, the virus that causes genital herpes will remain in the body for life after initial infection, often causing outbreaks 2 or 3 times a year. The frequency and severity of outbreaks tends to diminish over time.
Several types of medical tests are used in herpes testing and diagnosis. Most common are:
- Herpes antibodies blood tests – These lab tests look for antibodies in the blood that are produced by the immune system in response to exposure to herpes simplex viruses, HSV-1 and HSV-2. These tests can be very useful as a routine screening tool in preventive health care or as a component of a complete annual STD screening. They can also be a good detection tool when herpes exposure or infection is suspected. However, since these tests look for antibodies to the viruses that cause herpes, and those antibodies take time to build up in the body, blood tests are best done a few weeks after a suspected exposure, and if results are negative, repeated after 12 to 16 weeks to ensure a clean bill of health.
- Cell culture tests – These tests can be done only in individuals who have active symptoms, and to produce reliable results, must be done within 48 hours of the appearance of sores. For this test, open sores are swabbed to obtain a sample of the fluids they contain, then that sample is checked for HSV. This test is most accurate during initial herpes outbreaks, with risk of false negatives rising when the test is used during recurrent outbreaks.
- PCR blood tests – These blood tests looks for the DNA of herpes viruses in the blood to detect HSV-1 and/or HSV-2 infection.
How is herpes treated?
There is no cure for herpes. However, symptoms can be minimized or suppressed with treatment. This typically includes ant-viral drugs, which can offer symptom relief and reduce risk of spreading herpes to others.
Johns Hopkins Medicine: