This is a blood test to detect antibodies to the herpes simplex virus, which may reflect recent or past infection with oral or genital herpes.

Blood is drawn from a vein, usually on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

The sample is taken to the laboratory and evaluated for the presence and quantity of antibodies.

No special preparation is necessary.

For infants and children:

The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

This test is done to detect if you have been infected with the herpes simplex virus 1 (HSV-1) or herpes simplex virus 2 (HSV-2). This test does not detect the virus itself. If antibodies to the virus are present, you have been infected with herpes simplex at some point in your life.

If the infection is very recent (few weeks to 3 months), antibodies may not be detected, but you may still be infected.

Approximately 70% of adults have been infected by HSV-1 and have antibodies against the virus. About 20% of adults will have antibodies against the HSV-2 virus.

The presence of antibodies indicates that you have been infected with herpes-simplex recently or at some point in the past. Certain patterns of antibodies can sometimes help determine whether the infection is recent.

If you have been infected within the past weeks to 3 months, your body may not have yet mounted an antibody response and the test may be falsely negative. This time frame is called the window period.

Herpes simplex virus stays in your system once you have been infected. It may be dormant and cause no symptoms, or intermittently reactivate (flare-up) and cause symptoms. This test is not helpful in determining whether you are having a flare or reactivation.

HSV-2 is commonly associated with genital herpes while HSV-1 is usually associated with cold sores (oral herpes), however, some cases of genital herpes are caused by HSV-1 and vice versa. Certain antibody tests against herpes simplex are not always able to definitively distinguish between HSV-1 and HSV-2, hence results should be interpreted with caution and discussed with your health care provider.

Risks associated with having blood drawn are slight:

• excessive bleeding
• fainting or feeling lightheaded
• hematoma (blood accumulating under the skin)
• infection (a slight risk any time the skin is broken)
• multiple punctures to locate veins

While herpes virus 1 or 2 are usually only active episodically, once in your system, they remain for the rest of your life. Consult your medical provider about special measures you may need to take if you develop symptoms as well as how to decrease your risk of transmitting the virus(es) to susceptible people. Condoms may not fully protect against HSV viruses.

Wald A, Ashley-Morrow R. Serological testing for herpes simplex virus (HSV)-1 and HSV-2 infection.Clin Infect Dis 2002;35 (Suppl 2):S173-82.

Turner KR, Wong EH, Kent CK, et al. Serologic herpes testing in the real world.  Validation of new type-specific serologic herpes simplex virus tests in a public health laboratory. Sex Trans Dis 2002;29:422-425