Tests to Diagnose Genital Herpes

Medically Reviewed by Traci C. Johnson, MD on September 18, 2023
3 min read

Genital herpes is a common STD; however, many people who have this sexually transmitted disease don't know they have it. Genital herpes frequently has no symptoms, so you can be infected and contagious without knowing it. When symptoms do occur, they can easily be mistaken for something else. Without adequate testing, you risk infecting a sex partner and not getting medications that can help reduce the severity of your symptoms and accelerate healing.

You may have a sore on your genitals, buttocks, thighs or anus, and if so, your health care provider can perform tests to see if they are caused by the herpes virus.

Genital Herpes Tests

Tests used to diagnose or screen for genital herpes include:

  • PCR test: The PCR test can tell if you have genital herpes even if you don't have symptoms. The PCR test looks for pieces of the virus's DNA in a sample taken from cells or fluids from a genital sore or the urinary tract. This is a commonly used test to diagnose genital herpes and is very accurate.
  • Cell culture: During the exam, your health care provider can take a sample of cells from a sore and look for the herpes simplex virus (HSV) under a microscope.

Cell culture or PCR test may give a false-negative result if the sores have begun healing or if you are recently infected. A false-negative test shows you don't have the condition when in fact you do. False-positive test results are possible, too. If you test positive, but your risk for getting the virus is low, you may need further testing.

Other Genital Herpes Tests

Blood tests can detect the HSV antibodies, which are proteins produced by the immune system in response to an infection. With direct fluorescent antibody testing, a solution containing HSV antibodies and a fluorescent dye is added to the sample of cells. If the virus is present in the sample, the antibodies stick to it and glow when viewed under a special microscope. The test can’t tell you when you were infected – and it may take weeks for antibodies to form.

Antibody tests can tell the difference between the two types of HSV. It's important to know which type you have. If you're infected with type 2 (HSV-2), you may have outbreaks more often than you would with type 1 (HSV-1), which also causes cold sores that appear on the lips and around the mouth.

Unfortunately, an antibody test only tests whether you have been exposed or ever had herpes virus. It is helpful, but does not diagnose a specific outbreak.

Before you visit your health provider to be tested for genital herpes, first read Preparing for Your Doctor Visit. To get the most out of your exam, print and take along 10 Questions to Ask Your Doctor.

If you are diagnosed with herpes, you have many decisions to make. Do you want to take medication? Which one? Should you take medicine every day or only when you have symptoms? To better understand your choices, see Treatment Options and this helpful chart, Medications Chart.

For more information and help understanding words you may hear about genital herpes, see Resources and the Glossary.