Getting tested for genital herpes depends on whether you currently have symptoms. If you have visible sores or blisters, a provider can swab the lesion directly. If you have no symptoms but want to know your status, a blood test checks for antibodies your immune system produces in response to the virus. Each method has different strengths, limitations, and timing requirements.
Swab Testing for Active Outbreaks
If you have blisters, sores, or ulcers in the genital area, the most reliable way to test is a swab taken directly from an open lesion. A provider uses a small cotton or synthetic swab to collect fluid or cells from a sore that hasn’t yet crusted over or started healing. The fresher the lesion, the more accurate the result. Once a sore begins scabbing, there’s far less virus to detect, and the test becomes unreliable.
Two types of swab tests exist: viral culture and PCR (polymerase chain reaction). PCR is the preferred method because it’s significantly more sensitive. In head-to-head comparisons, PCR detected the virus in roughly twice as many confirmed cases as culture did. Both tests have a 100% specificity rate, meaning a positive result on either test is trustworthy. But culture misses a substantial number of real infections, so a negative culture doesn’t rule herpes out the way a negative PCR does. If your provider offers you a choice, PCR is the better option.
Swab tests also tell you which type of herpes you have: HSV-1 or HSV-2. This matters because the two types behave differently over time. HSV-1 in the genital area tends to recur less frequently than HSV-2.
Blood Tests When You Have No Symptoms
If you don’t have any visible sores, a blood test is the only way to check for herpes. Blood tests don’t detect the virus itself. Instead, they look for IgG antibodies, proteins your immune system creates after being exposed to HSV-1 or HSV-2. A type-specific IgG test can tell you which strain you carry.
Timing matters. IgG antibodies don’t appear immediately after infection. They take at least two weeks to develop, and in some people, it can take up to 12 weeks for antibody levels to reach detectable thresholds. If you were recently exposed and test too early, you could get a negative result even though you’re infected. For the most reliable blood test result, wait at least 12 weeks after the possible exposure.
One important note: avoid IgM testing. Some providers still order it, but IgM antibodies are not useful for diagnosing herpes. They can appear during both new and recurring infections, cross-react between HSV-1 and HSV-2, and produce misleading results. A type-specific IgG test is what you want.
The False Positive Problem
The most widely used screening blood test for HSV-2 has a known weakness: it can produce false positives, especially in people at low risk for the virus. Results come back as an index value rather than a simple positive or negative. Anything above 1.10 is considered positive, but values in the range of 1.10 to 3.50 have a high rate of being false positives.
The CDC recommends that any result falling in that low-positive range (1.10 to 3.50) be confirmed with a second, more accurate test. The gold standard confirmatory test is the Western blot, performed at the University of Washington’s clinical virology lab in Renton, Washington. It requires a blood draw, and the sample must be frozen and shipped on dry ice if sent from an outside lab. Your provider can order it, or you can contact the lab directly for instructions. If your initial screening result falls in the low-positive zone, don’t accept it as a final answer without confirmatory testing.
Where to Get Tested
You have several options for getting a herpes test. Your primary care provider or OB-GYN can order either a swab or blood test. Planned Parenthood and other sexual health clinics offer testing, often on a sliding fee scale. Some county public health clinics provide STI services at low cost. For example, county sexual health clinics may charge around $40 per visit for a comprehensive exam and testing, with fee waivers available for those who can’t pay.
Be aware that not all clinics offer blood testing for herpes. Some only perform swab tests on active lesions. County and public health clinics in particular may limit herpes testing to swabs, so call ahead if you’re looking for a blood test without symptoms. At-home test kits that use a finger-prick blood sample are also available through several online services, though the same false positive considerations apply to their results.
Why Routine Screening Isn’t Standard
You might be surprised to learn that herpes is not included in a standard STI panel. When you ask a provider for “full STI testing,” herpes is almost never part of it unless you specifically request it. This isn’t an oversight. The CDC does not recommend routine herpes screening for people without symptoms because of the high false positive rate in blood tests and because a positive result in someone who has never had symptoms rarely changes medical management. The psychological impact of a diagnosis, particularly one that may be a false positive, is considered a real harm.
That said, testing makes sense in certain situations: if you have symptoms that could be herpes, if a sexual partner has been diagnosed, if you want to know your status before a new relationship, or if you’re pregnant (since herpes can be transmitted to a newborn during delivery). You may need to explicitly ask your provider to add herpes to your test panel, because it won’t be included automatically.
What to Expect From Results
Swab test results typically come back within a few days. A positive swab is definitive: you have herpes, and the result will specify HSV-1 or HSV-2. A negative swab doesn’t fully rule it out, especially if the lesion was already healing when sampled.
Blood test results also return within a few days and report separate values for HSV-1 and HSV-2. A negative result (index below 0.90) means no antibodies were detected. A value between 0.90 and 1.10 is considered equivocal, meaning the test couldn’t determine a clear answer, and retesting in a few weeks is recommended. A value above 1.10 is positive, but as noted, anything between 1.10 and 3.50 for HSV-2 warrants confirmatory testing. Values above 3.50 are much more likely to be true positives.
Keep in mind that a positive HSV-1 blood test doesn’t necessarily mean genital herpes. Most HSV-1 infections are oral (cold sores), and the blood test can’t tell you the location of infection. Only a swab from a genital lesion can confirm that HSV-1 is present in the genital area.