A 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. Once you have been exposed to herpes, you develop the antibodies even though the virus will be dormant in your body. So the lab reading that you got does not mean that you have herpes, but instead that you once were exposed and your body developed the antibody for the virus.
Of course you can run the test again but it will probably show the same result. I thought you might like to look at the website below.