Herpes Simplex Virus Type 1 (HSV-1) IgG Antibody, Serum/Plasma

What Does This Test Measure?

The test detects **IgG antibodies**—a type of protein produced by your immune system in response to past exposure to HSV-1. Unlike IgM antibodies, which appear shortly after infection, IgG antibodies remain in your blood for a longer period, often lasting years or even a lifetime after initial infection. This test is used to confirm whether you’ve had HSV-1 at some point, even if you don’t currently have active symptoms.

Why Might You Need This Test?

A doctor may recommend this test if you have concerns about past exposure to HSV-1, such as after a sexual encounter with someone who has HSV-1, or if you’re investigating unexplained recurrent cold sores or other symptoms linked to herpes. It can also be part of screening for immunocompromised individuals or those with recurrent infections.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, typically drawn from a vein in your arm. The process takes a few minutes, and you can resume normal activities afterward. If you’re on blood-thinning medications, let your healthcare provider know before the test.

What the Results Mean

A positive result means your body has produced IgG antibodies against HSV-1, suggesting past exposure. A negative result indicates no detectable antibodies, meaning you likely haven’t been exposed to HSV-1 in the past year or two. However, results don’t confirm current infection status—active HSV-1 infection would require testing for IgM antibodies or viral culture.