An immunoglobulin G (IgG) blood test is used to diagnose herpes simplex virus

(HSV) infection. This test does not detect the virus. Rather, it detects the antibodies, or

immune proteins, that your body produces in response to the viral infection.A positive result

indicates that HSV antibodies were detected and the patient has an active outbreak or

past infection. Negative results from antibody testing indicate that HSV antibodies weren't

detected in the sample.