Can Herpes Tests Give a False Positive? What You Need to Know

Receiving a positive herpes test result can be overwhelming—especially if you don’t have symptoms or weren’t expecting it. In some cases, the result may not be accurate. While herpes blood tests are generally reliable, false positives do happen. Knowing why they occur and what to do next can help you make clearer, more confident decisions.

This page explains what false positives are, how often they happen, and what steps you can take to confirm your results. If you’re unsure whether your test was accurate, you’re not alone—and there are ways to follow up that are fast, discreet, and affordable.

What Is a False Positive?

A false positive occurs when a test indicates you have herpes, but you don’t actually carry the virus. Most herpes tests look for IgG antibodies—proteins your immune system creates in response to an infection. While these tests are generally accurate, especially for HSV-2, they’re not perfect.

In some cases, low levels of cross-reactive antibodies can trigger a positive result even when HSV isn’t present. This is more common with HSV-1 and in the low-positive range for HSV-2.

How Common Are False Positives?

False positives for HSV-2 are relatively rare at higher index values but become more likely when results fall into the “low positive” range. The CDC considers an index value between 1.1 and 3.5 to be a low positive, meaning the signal detected by the test was weak. Some people in this range may not have herpes at all.

Research suggests that up to 50% of people with index values under 3.5 could receive a false positive. That’s why confirmatory testing is often recommended when results fall into this range—especially for people without symptoms or a known exposure.

Why Do False Positives Happen?

Several factors can contribute to a false positive result:

• Timing: Testing too soon after exposure can lead to both false positives and false negatives. Antibodies take time to develop, and your immune system’s early response may produce cross-reactive signals.
• Low Index Values: As mentioned above, values below 3.5 should often be followed by confirmatory testing.
• Test Sensitivity: Type-specific IgG tests are better than older methods, but some still have higher rates of false positives for HSV-1 in particular.
• Cross-Reactivity: Antibodies for other viruses—like CMV or EBV—can occasionally interfere with herpes antibody tests.

Understanding these limitations doesn’t mean the tests are unreliable—it just highlights the importance of interpreting results carefully, especially when the numbers are borderline or you have no symptoms.

What Should You Do Next?

If you’ve received a positive result but have never had symptoms, or your result came back with a low index value, don’t panic. You have a few good options:

• Retest: Use a different provider or wait a few weeks and retest to confirm your result. Antibody levels can fluctuate, and retesting can bring clarity.
• Confirmatory Test: STDCheck offers separate HSV-1 and HSV-2 tests so you can retest only the one in question. They also offer physician consultations if needed.
• Talk to a Specialist: If you’re unsure how to interpret your index value, myLAB Box offers a free telehealth consult with their herpes test to help you understand what your result means.

What If Your Second Test Is Positive Too?

If a second test confirms your result, it’s important to remember that herpes is common, manageable, and doesn’t define your health or identity. Millions of people live with HSV every day—many without symptoms or complications. Suppressive treatment is available and effective, and open communication with partners goes a long way toward reducing stigma.

We cover more about ongoing care and treatment options in our herpes treatment guide.

A Positive Result Isn’t Always the Final Word

False positives are real, and you’re not wrong to question your result—especially if it came as a surprise. Following up with a second test or speaking to a provider can offer peace of mind and ensure that your next steps are based on the clearest information possible.

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