If you've just gotten herpes test results and you're staring at numbers that don't quite make sense (or worse, results that seem to contradict each other) take a breath. You're not alone, and herpes testing is genuinely more confusing than it should be. Let's walk through what each test measures, what those numbers actually mean, and what to do when the results aren't clear-cut.
Why herpes testing is so confusing
Here's the thing most people don't realize: herpes testing isn't like a pregnancy test where you get a simple yes or no. There are multiple types of tests, each with different strengths and limitations. Results can come back as numbers on a scale rather than a clear "positive" or "negative." And depending on when you get tested, you might get a completely different result.
If you're feeling confused or frustrated right now, that's a completely rational response. The testing itself is genuinely messy. So let's sort through it together.
The three main herpes tests
1. Swab test (PCR or viral culture)
What it does: Tests fluid from an active sore to detect the herpes virus directly.
When it's used: During an active outbreak, ideally within the first 48 hours of a new sore appearing.
The catch: Swab tests are highly accurate when sores are fresh and blistering, but their accuracy drops fast as lesions start to heal. If your doctor swabs a sore that's already crusting over, a negative result doesn't necessarily mean you're herpes-free. It may just mean there wasn't enough active virus left to detect.
This is one of the most common sources of confusion, and one of the most frequent things people in our community deal with. "My swab came back negative, but I know something isn't right." If that's you, trust your instinct. A negative swab during a healing lesion doesn't rule out herpes. Ask your doctor about a blood test or request another swab the next time symptoms appear, early, before things start healing.
2. IgG blood test (type-specific)
What it does: Detects antibodies your immune system makes in response to herpes. Can distinguish between HSV-1 and HSV-2.
When it's used: Anytime, doesn't require active symptoms. Best done 12 or more weeks after potential exposure to allow antibodies to develop.
The catch: The IgG test returns a numerical index value, not just positive or negative. And that number matters a lot (more on this below). The test is roughly 92–95% accurate for HSV-2 and about 91% accurate for HSV-1, which sounds high until you realize that means 5–9% of results could be wrong.
Important: The testing window is real. If you get tested too soon after exposure (less than 4 weeks), your body may not have produced enough antibodies yet, and you could get a false negative. For the most reliable results, wait at least 12 weeks.
3. Western Blot
What it does: The gold standard confirmatory test for herpes. Over 99% accurate. Distinguishes HSV-1 from HSV-2.
When it's used: To confirm or rule out herpes when IgG results are unclear, equivocal, low positive, or conflicting with your symptoms.
How to get it: The Western Blot is only available through the University of Washington Clinical Virology Laboratory. Your doctor can order it, or you can contact the lab directly at (206) 520-4600 to request a test kit. It involves a blood draw that gets sent to the UW lab for analysis.
Why it's not the default: It's more expensive, takes longer to process, and isn't widely available at standard labs. But when you need a definitive answer, it's the best tool we have.
A note on the IgM test
You may see an "IgM" test offered. Skip it. The CDC specifically recommends against IgM testing for herpes because it has a high false-positive rate, can't reliably distinguish between HSV-1 and HSV-2, and can't tell you whether an infection is new or old. If your doctor orders an IgM test, ask for a type-specific IgG instead.
Understanding your IgG index value
This is where most of the confusion lives, so let's break it down clearly.
When you get an IgG blood test, you'll receive a number (the "index value") for HSV-1 and/or HSV-2. Here's what that number means:
Below 0.90. Negative
No antibodies detected. If tested 12+ weeks after exposure, this is reliable. If tested earlier, consider retesting later.
0.90 , 1.10. Equivocal (the gray zone)
The test can't determine positive or negative. Retest with IgG in 4–6 weeks or go straight to Western Blot for a definitive answer.
1.10 , 3.50. Low positive (may be a false positive)
Up to 50% of HSV-2 values in this range are false positives. Strongly consider Western Blot confirmation, especially if you've never had symptoms.
Above 3.50. Positive (high confidence)
Very likely a true positive. False positives at this level are rare.
Here's what's important to understand: a low positive is not the same as a definite positive. If your HSV-2 IgG came back at 1.04, 1.2, or even 2.5, there's a real chance it could be a false positive, especially if you've never had symptoms. The only way to know for sure is a Western Blot.
Common scenarios (and what to do)
"I tested positive but I've never had symptoms"
This is more common than you might think. Up to 80% of people with HSV-2 don't have symptoms they recognize as herpes. So a positive blood test without symptoms doesn't mean the result is wrong, it may mean you're one of the many people who carry the virus without noticeable outbreaks.
That said, if your IgG value was between 1.10 and 3.50, it's worth getting a Western Blot to confirm. At higher values (above 3.50), the result is very likely accurate even without symptoms.
"My swab was negative but I'm sure it's herpes"
Trust your instincts here. As we covered above, swab tests have a real false-negative rate, especially if the sore was already healing when it was swabbed. If your symptoms keep recurring in the same spot, especially with prodrome signs like tingling or burning beforehand, ask your doctor to:
- Swab again during the very next outbreak, as early as possible, ideally within the first 24–48 hours
- Run a type-specific IgG blood test (if it's been 12+ weeks since potential exposure)
"My IgG came back equivocal, what now?"
An equivocal result (0.90–1.10) just means the test couldn't make a call. It's not a soft positive, it's genuinely inconclusive. Your options:
- Retest with IgG in 4–6 weeks. Sometimes antibody levels are still developing and a repeat test will give a clearer answer.
- Request a Western Blot. If you want a definitive answer now rather than waiting and retesting, the Western Blot will settle it.
"My IgG was low positive (like 1.04 or 1.8), do I really have herpes?"
Maybe. Maybe not. Low positive IgG values for HSV-2 (between 1.10 and 3.50) have a false-positive rate that can be as high as 50% in people who are at low risk. That's a coin flip, not exactly reassuring.
If your value is in this range and you've never had symptoms, a Western Blot is strongly recommended before accepting the diagnosis. Many people in our community have gone through this exact experience, getting a low positive, spiraling emotionally, and then discovering through Western Blot that the original result was wrong.
You deserve a clear answer. Don't accept uncertainty when a better test exists.
"I tested positive, then negative. I'm confused"
Fluctuating results usually happen with low-positive IgG values near the cutoff. Antibody levels can hover right around the threshold, producing different results on different days. Again, the Western Blot is your friend here. It cuts through the ambiguity.
The emotional side of testing limbo
Let's be real: waiting for test results (or trying to make sense of confusing ones) can be genuinely awful. The googling at 2 AM. The spiraling. The "what if" conversations in your head that go nowhere good.
If that's where you are right now, here's what I want you to hear: whatever the result turns out to be, you're going to be okay. If it's positive, herpes is one of the most manageable conditions out there, and millions of people are living full, connected, vibrant lives with it. If it's negative, you can stop worrying. Either way, clarity beats limbo.
And if you're in that space where you've just found out you have herpes and the ground feels shaky, know that what you're feeling is normal and it gets so much better. Start with our free e-book on herpes and disclosure, it's helped tens of thousands of people find their footing. Or check out herpes support groups where you can connect with others who've been exactly where you are.
Quick reference: which test should you get?
- Active sore or blister right now? Swab test (PCR), get it done ASAP while the sore is fresh.
- No symptoms, but want to know your status? Type-specific IgG blood test. Wait 12+ weeks after potential exposure for reliable results.
- IgG came back equivocal (0.90–1.10)? Retest IgG in 4–6 weeks, or request a Western Blot.
- IgG came back low positive (1.10–3.50)? Western Blot to confirm, especially if you've never had symptoms.
- Swab was negative but symptoms keep coming back? Re-swab early in the next outbreak + get an IgG blood test.
- IgG results keep fluctuating? Western Blot for a definitive answer.
Testing can feel like a maze, but you don't have to navigate it alone. Talk to your doctor about which test makes sense for your situation, and if they're not familiar with the nuances of herpes testing (many aren't), don't be afraid to advocate for yourself or seek a second opinion. You deserve clear answers, and you're allowed to push for them.
For more on the basics, see our overview of herpes tests. And for support navigating what comes next (whatever the result) explore one-on-one coaching.
