Herpes testing goes by several names depending on the method used. The most common are HSV PCR (a molecular swab test), HSV viral culture (growing the virus from a sore), and HSV IgG antibody test (a blood draw). You might also see them listed on lab orders as “HSV DNA,” “herpes simplex viral culture,” or “HSV-1/HSV-2 antibodies.” Which test you get depends mainly on whether you have visible sores at the time of testing.
Swab Tests for Active Sores
If you have a blister, sore, or unusual lesion, your provider will likely swab it directly. That sample then goes to a lab for one of two tests.
HSV PCR (polymerase chain reaction) is the preferred method. It detects genetic material from the herpes virus in the swab sample and is both faster and more accurate than a culture. In head-to-head comparisons, PCR catches the virus in samples that culture misses roughly half the time. You may also see this called an HSV NAAT (nucleic acid amplification test), which is the broader category PCR falls under.
HSV viral culture is the older approach. The lab takes cells from your swab and grows them to see if herpes virus appears. It’s highly specific, meaning a positive result is reliable, but its sensitivity is only around 50% compared to PCR. That means a negative culture doesn’t rule out herpes. Cultures also take longer, sometimes several days, while PCR results often come back within one to two days.
Both swab tests can tell you whether the infection is HSV-1 or HSV-2, which matters for understanding how often outbreaks may recur and how likely transmission is.
Blood Tests When There Are No Sores
Without an active lesion to swab, the only option is a blood test that looks for antibodies your immune system has built against the virus. This is called a type-specific HSV IgG antibody test. It can distinguish between HSV-1 and HSV-2 infections, though it cannot tell you where on your body the infection is or exactly when you were exposed.
IgG antibodies take time to develop after an initial infection. The antibody response begins 2 to 12 weeks after exposure, with type-specific antibodies sometimes taking up to 6 months to reach detectable levels. Testing too soon after a possible exposure can produce a false negative simply because your body hasn’t built enough antibodies yet.
You may come across references to an HSV IgM test, which is a different type of antibody test. IgM testing is not recommended because it is unreliable for identifying new infections and frequently cross-reacts with other herpes viruses, producing misleading results.
False Positives and Confirmatory Testing
The FDA has issued a reminder that HSV-2 blood tests can produce false positive results. The risk goes up if you were tested too soon after potential exposure, if your overall risk of infection is low, or if your result falls in the “low positive” range near the test’s cutoff value.
Results from IgG blood tests are typically reported as non-reactive (no antibodies detected), indeterminate (borderline), or reactive (antibodies detected). If your result is reactive but falls in the low-positive zone, guidelines recommend confirmatory testing. The two main confirmatory options are the Biokit rapid test and the Western blot, which is considered the gold standard for resolving uncertain results.
Who Should Get Tested
Routine herpes blood screening is not recommended for the general population or for pregnant women without symptoms. The CDC reserves blood testing for specific situations: recurrent or unusual genital symptoms where a swab test came back negative, a clinical diagnosis that was never confirmed by a lab, or when a sexual partner has genital herpes. People at higher risk, including those being evaluated for other STIs (especially with 10 or more lifetime partners) and people with HIV, may also benefit from type-specific blood testing.
If you have a visible sore, the most straightforward path is getting it swabbed for PCR testing while the lesion is still fresh. Sores that have started to crust over or heal yield less reliable results because there’s less active virus to detect.
At-Home Test Kits
Several companies sell herpes test kits you can use at home. These typically involve a finger-prick blood sample that you mail to a lab for IgG antibody analysis. The convenience is real, but the same limitations apply: you still face the 2-to-12-week window period, the possibility of false positives in the low-positive range, and the inability to pinpoint the infection site. At-home kits also can’t swab a sore for PCR testing, so if you have an active outbreak, an in-person visit will give you a faster and more definitive answer.
What to Ask For
Herpes testing is not part of standard STI panels at most clinics. If you want to be tested, you generally need to request it specifically. When speaking with your provider, the clearest way to ask is for a “type-specific HSV IgG blood test” if you have no symptoms, or an “HSV PCR swab” if you have an active sore. Knowing these names helps you confirm that the right test is being ordered, since vague requests for “herpes testing” can sometimes lead to the less reliable IgM test or no test at all.