Finding the right tests…
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Finding the right tests…
ELISA
HSV 1 IgG looks for the antibody your body makes against herpes simplex virus type 1, the type most often linked to cold sores around the mouth, though it can infect the genital area too. A positive result means you were infected at some point, usually weeks to months ago, and the antibody stays with you for life; it does not tell your doctor where on your body the infection is, or when it happened. It's typically ordered when someone wants to know their exposure status without symptoms present, or before pregnancy, rather than as part of the full TORCH panel.
This is a type-specific IgG blood test using an ELISA-based method, reported as reactive, non-reactive, or a borderline/equivocal index value depending on the kit your lab uses. A low-positive index value carries a higher chance of being a false positive, so labs and doctors sometimes recommend a repeat or confirmatory test before treating a borderline result as definite. It typically takes several weeks after exposure for antibody levels to become reliably detectable.
HSV-1 is best known for cold sores, but it can just as easily cause genital herpes, and the split between the two is less clean-cut than it used to be. Oral-genital contact during oral sex now accounts for a large share of new genital HSV-1 infections, particularly in younger adults, so a positive HSV-1 IgG cannot tell you whether the exposure was oral, genital, or both.
Type-specific IgG antibodies build up over the first several weeks after infection and then persist indefinitely, which is why this test is used to check exposure status rather than to catch a fresh outbreak. Because most people acquire oral HSV-1 in childhood, sometimes decades before any genital symptoms would appear, a positive HSV-1 IgG is common and does not by itself explain genital symptoms. It is genuinely useful for a person weighing HSV-1 exposure before starting a new sexual relationship, or a partner of someone with known genital HSV-1 who wants to understand their own risk.
Guidance from the CDC notes that HSV-1 serologic testing does not tell oral from genital infection apart and generally is not the right test to confirm a genital sore is caused by HSV-1; a swab of an active sore, tested directly, is more reliable for that.
Not necessarily. HSV-1 classically causes oral cold sores, and most people acquire it in childhood, though it can also cause genital herpes through oral-genital contact. This test cannot tell your doctor which site is or was infected.
Type-specific IgG antibodies typically build up over the first several weeks after infection, so testing too soon after a suspected exposure can give a false negative.
No. Once IgG appears, it generally persists indefinitely, so a positive result confirms exposure at some point but not when.
A direct swab of an active sore, tested for the virus itself, is generally more reliable for confirming what's causing it right now than a blood antibody test. Ask your doctor which test suits your situation.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
It measures the same antibody, but here it is offered as a standalone HSV-1-specific test rather than bundled with Toxoplasma, Rubella, CMV, and HSV-2 testing.
Yes, type-specific IgG testing is designed to tell the two types apart, unlike older, non-specific herpes antibody tests.
It usually means no past HSV-1 exposure has been detected, though a very recent exposure can still test negative if antibodies haven't built up yet.