Laboratory Testing - Overview

Testing for the virus directly from the skin is useful if genital symptoms are present at the time of an office visit to a health care provider. Diagnosing herpes by just looking at a lesion or sore does not give an accurate diagnosis because many other infections or irritations can look just like herpes. As such, and because HSV is a chronic disease, confirmation of the diagnosis with a laboratory test is recommended by almost all medical authorities and by the Centers for Disease Control. When lesions or sores are present the physician or health care provider can swab the sore and submit the sample for detection of herpes simplex virus by growth in culture or by detecting parts of the virus in the material on the swab. Finding the HSV virus by any of these assays shows that HSV caused the lesion.

The one exception to this is that persons occasionally have more than one infectious agent in a single lesion (a "dual" infection). This may include HSV and another organism such as syphilis. In the United States, dual infection is quite uncommon. Dual infections are more common in some other areas of the world.

Another way to diagnose herpes is to detect antibodies in the blood that the body has made to fight off the virus after infection. These antibodies last for a lifetime after an infection. They can be detected by a blood test even if no signs or symptoms are present at the time the patient visits the doctor. Antibodies develop even when patients have never had symptoms of herpes.

Blood tests to identify antibodies are called "serology". Serology can help show that herpes infection has occurred in situations where it is difficult to obtain or to properly transport a sample for virus detection tests. If performed correctly, antibody tests can identify a person as having had an HSV-2 infection or an HSV-1 infection, or both viruses sometime in the past.

HSV blood tests are confusing to patients and to clinicians as well. Unfortunately there are many claims about blood tests--some less accurate than others. This has led to confusion about when blood tests should be done and which tests are accurate. This area of testing is so important, we have devoted an entire section of this website to providing the most current information on HSV serology. Click here to read more about HSV type specific serology.

We have given an overview on the laboratory tests to use for diagnosis. Much more information is given in separate sections below on Viral Culture, HSV FA, Viral PCR, and Serology. There are other things a health care provider can and should consider in evaluating a person with genital lesions, sores, or recurrent symptoms that could be due to herpes.