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The Test Sample
What is being tested?
Herpes is a common viral infection caused by the herpes simplex virus (HSV). The virus exists as two main types, HSV-1 and HSV-2. Herpes simplex virus testing identifies the presence of the virus in a sample from a blister, sore or fluid to diagnose an acute herpes infection or detects herpes antibodies in the blood to determine previous exposure to herpes.
Both HSV-1 and HSV-2 are contagious and periodically cause small fever blisters (vesicles) that break to form open lesions. HSV-1 primarily causes blisters or "cold sores" around the mouth, while HSV-2 usually causes lesions around the genital area; however, either one can affect the oral or genital areas.
The herpes simplex virus can be passed from person to person through skin contact while the sores are open and healing and sometimes when there are no visible sores. HSV-2 is frequently a sexually transmitted disease, but HSV-1 also may be acquired during oral sex and found in the genital area. According to the American Sexual Health Association, about 50% of adults in the U.S. have HSV-1 and about 17% have HSV-2. Because symptoms may be mild, however, 90% of those who have HSV-2 may be unaware that they have been infected.
When someone is first infected, the person may have obvious and painful blisters at the site of infection, which usually appear within two weeks after the virus is transmitted. The lesions generally heal within two to four weeks. The blisters 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 blisters and even flu-like symptoms such as fever and swollen glands. However, not everyone develops blisters, and sometimes symptoms are so mild that they are unnoticeable or mistaken for something else, such as insect bites or a rash.
Once someone is infected and the initial infection resolves, the person will harbor the HSV in a latent form. During periods of stress or illness, the virus may reactivate.
People with conditions that cause their immune system to be suppressed, such as those with HIV/AIDS or those who have had an organ transplant, may have more frequent and serious outbreaks of HSV. While there is no cure for herpes, antiviral medications can suppress outbreaks and shorten the duration of symptoms and active shedding of virus.
Rarely, the virus can cause neonatal herpes when a woman transmits the virus to her baby during a vaginal delivery. Neonatal herpes symptoms appear during the first month of life and, if left untreated, can cause long-term damage to a baby's health. A pregnant woman who has been diagnosed with herpes may be monitored regularly prior to delivery to identify a reactivation of her infection, which would indicate the necessity for a caesarean section to avoid infecting the baby.
The herpes simplex virus can be transmitted to the brain, causing encephalitis. This illness can be fatal or cause serious, permanent neurological problems in those who survive.
How is the sample collected for testing?
A healthcare practitioner will take a swab or scraping from a blister or sore in the genital area. A sample of cerebrospinal fluid (CSF) may be collected from the spinal column (spinal tap) when meningitis or encephalitis is suspected. For antibody testing, a blood sample is obtained by inserting a needle into a vein in the arm.
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.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.