Doctors can often identify genital herpes by the typical appearance of skin lesions. However, this window of opportunity may be easily missed if the lesions have already healed. The doctor may choose to test for other sexually transmitted diseases (STDs) based on your symptoms, medical history, and sexual history.

Many people may feel anxious or embarrassed about discussing their sexual history, but an accurate history is important to guide your evaluation. Home test kits are widely available, but they are not as accurate as testing at a doctor's office. If you choose to use a test kit, it is important to follow-up with a doctor, regardless of the results.

Testing can distinguish between herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2), which will help guide your treatment plan.

Viral Culture

If sores are present, a swab will be brushed over an open sore or blister to collect some fluid and cells. The swab is then tested to see if the virus is present. It is recommended that this culture test be taken soon after symptoms appear, ideally when blisters are present and fluid-filled.

This type of test is not always reliable. If the sores are healed and dry, the test may give a false-negative. A false-negative occurs when a test reports that herpes is not present when it actually is.

Polymerase Chain Reaction

Polymerase chain reaction (PCR) is a molecular diagnostic test. It detects genetic material of the virus. Like the viral culture, it can give a false-negative, but the PCR test is much more accurate.

Blood Tests

Blood tests may be done to look for HSV antibodies. Antibodies are created by the immune system to fight foreign materials like viruses. Specific antibodies are made for specific viruses. If the blood tests show HSV antibodies, you are most likely infected with the virus. The main limitation of testing for HSV antibodies is that when the antibodies are present, there is no way to distinguish between HSV infection causing cold sores around the mouth versus HSV infection causing genital herpes. However, the presence of either condition places partners at risk for genital herpes transmission.

Costs may prohibit some people from seeking testing. Local community health or family planning centers may offer free or lower cost testing services.