How Herpes Is Diagnosed

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Herpes simplex virus (HSV) types 1 and 2 can be diagnosed based on the appearance of lesions (if present), as well as with laboratory tests.

In general, if you do not have symptoms, there is no need for you to have any diagnostic testing for HSV type 1—the type that causes cold sores. However, if you may have been exposed to HSV type 2, a sexually transmitted infection (STI) that causes genital sores, you may need to be tested even if you do not have lesions.

This article explains the tests used to diagnose herpes, including why a urine test is not typically used to detect herpes. It also discusses how you can monitor for signs of herpes at home.

herpes diagnosis
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Self-Checks

Both HSV-1 and HSV-2 can cause visible skin lesions. It is important that you see a healthcare provider, especially if you've never had an outbreak before. Most healthcare providers do not routinely test for herpes unless you specifically ask.

Cold sores in and around the mouth usually are due to HSV-1. If you are concerned about HSV-2 symptoms due to an STI, or think you may have been exposed, watch for:

Additional symptoms typically linked to a first episode of HSV-2 infection can include:

Once you've had herpes, you can learn to recognize recurrences of the lesions. But if your recurrences are more severe or if the lesions look different than usual, then you should seek an evaluation.

Cold sores in the mouth are usually caused by HSV 1, and genital herpes infections are usually caused by HSV 2. However, either virus can infect either location. Herpes outbreaks usually appear as one or more blisters in clusters. The blisters may be sores.

If you or your child experience pain or tingling around or inside the mouth or on the tongue, you can feel and look for bumps and blisters around the painful area, which may indicate HSV-1.

If you have pain in or around the genital area, or if you have pain with urination or sexual activity, it may indicate HSV-2. Check for lesions if you think you could have been exposed to the infection. Know, though, that genital herpes infections are often asymptomatic.

Labs and Tests 

If you have symptoms of HSV type 1 or 2, your healthcare provider can diagnose a herpes infection by looking at your skin and/or by swabbing the sores to test for the herpes virus.

If you do not have obvious symptoms, a blood test can help determine whether you have an infection. 

Urine tests are typically not used to diagnose HSV-1 or HSV-2 infections. Lab tests rely on swabs of cells found in vaginal tissue or sores, or vesicular fluid. Some labs reject urine specimens for herpes tests. Urine tests are not considered accurate enough for herpes, though many urine STI screenings test for chlamydia and gonorrhea.

Swab Testing

The gold standard for herpes diagnosis is a viral culture test or nucleic acid amplification test (NAT) of a sample of skin, crust, or fluid from a lesion. This is usually obtained with a gentle swab of the area.

A viral culture is a test that allows the virus to grow in a laboratory setting. The NAT tests for the genetic material of the virus in the sample.

These tests should only come back positive if you have the virus present in the lesion. In general, the results of the test are reliable if you have active lesions.  

Herpes Blood Tests

It is possible to screen for asymptomatic herpes infections using a blood test. Herpes blood tests can detect antibodies to the herpes virus.

You form these proteins when you need to fight an infection. Generally, it takes about two weeks for your body to produce enough antibodies against herpes to be detectable.

The presence of antibodies is evidence that your body has confronted an infection, either recently or in the past. There are two kinds of blood tests for herpes:

  • IgM tests detect short-lasting antibodies that form to fight the virus shortly after an infection has occurred.
  • IgG tests detect long-lasting antibodies that your body makes to fight the virus.

Several different brands of blood tests are used to detect viral proteins, and there are pros and cons for each. Sensitivity and specificity of tests refer to the accuracy with which a condition is detected when present (sensitivity) and reliability of a negative test result (specificity).

The accuracy of various HSV-2 tests includes:

  • HerpeSelect HSV-2 test: 99% sensitivity, 81% specificity
  • Biokit HSV-2 Rapid Test: 84% sensitivity, 95% specificity

It is difficult to know how long it takes for blood tests to become positive after infection with HSV-1, and the tests are associated with a high false positive rate. However, testing before antibodies develop can lead to false negative results.

In general, it usually takes around two weeks for symptoms to appear after you have been infected with HSV type 1 or 2. If you do not have lesions that can be swab tested, it is a good idea to wait at least a month or two after your exposure before getting an HSV-2 antibody test. This is because it takes time for your body to make antibodies that can be detected in the blood.

There is some possibility that herpes blood tests may detect antibodies to similar viruses. This result would lead to a false-positive result, suggesting you have the infection when you don't.

If you have a strong reason to believe that you have been infected, consider getting retested after six months because some of the tests take longer to yield a positive result.

In Newborns

The diagnosis of neonatal herpes—an infection passed to a child during or after childbirth—is challenging.

Generally, babies are not screened for herpes infection. Symptoms such as lesions around the mouth or eye may alert caregivers that there is a problem. This should prompt diagnostic testing, which can be done using a swab sample.

However, more complicated neonatal herpes infections, such as encephalitis (infection of the brain), require specific tests such as a spinal tap.

Differential Diagnoses

There are a few other conditions that can be confused with cold sores or genital herpes. Some of these are quite serious, and it is not safe for you to self-diagnose.

Typically, these conditions can be distinguished from herpes with a medical examination or with laboratory tests.  

  • Canker sores: Canker sores are usually red, raised sores with a painful, raw, whitish pit in the center. They may be present in the mouth, and they tend to occur as a result of oral trauma. The initial painful sensation of canker sores and cold sores is similar, but the lesions look different. Canker sores do not test positive for herpes simplex virus. 
  • Syphilis: An STD that produces painless genital sores, syphilis can be confused with herpes. Your healthcare provider may be able to tell the difference by visually inspecting the lesions. If you have syphilis, your blood tests should be positive for Treponema pallidum, the bacteria that causes the infection.
  • Medication reaction: Medications can cause allergies and sensitivity reactions, which may manifest as a rash. This is not generally common in the genital area, but it can often occur around the lips and mouth. 
  • Cancer/pre-cancer: Lesions in and around the genital area can be signs of cancer. Cancerous or pre-cancerous lesions should not have blisters, which are a common characteristic of HSV-induced lesions. But if your healthcare provider needs to distinguish between cancer and herpes, a swab or a needle biopsy (sample of the lesion) can differentiate the two conditions.
  • Concurrent HSV-1 and HSV-2: If you have HSV-1 or HSV-2, you can also become infected with the other. These are different viruses and having one of them does not cause or prevent the other. See your healthcare provider if you develop sores in a new location. 

Most healthcare providers do not routinely test for herpes unless you specifically ask or have symptoms including genital pain, redness, swelling, sores, or blisters. If you have been exposed to genital herpes or would like to be tested, talk to your healthcare provider. 

How Is Herpes Treated?

Herpes is a viral infection that affects your body for a lifetime, and it can be managed but not cured. Options include over-the-counter treatment for oral cold sores, like Abreva (docosanol) cream. Pain relief medications like Advil (ibuprofen) can help. Antiviral medications like acyclovir can be used to treat genital herpes.

Keep in mind that treatment drugs and doses can change depending on whether it's your first herpes outbreak, or whether it's a recurrence of HSV-1 rather than HSV-2. For example, 400 milligrams (mg) of acyclovir given three times per day, for seven to 10 days, is recommended for a first HSV-2 outbreak; treatment for a recurring HSV-2 episode can be doubled to 800 mg, twice a day for five days instead.

Your healthcare provider will choose a treatment plan based on your specific infection and medical history.

Summary

Herpes infections are typically diagnosed based on test results, often but not always in the presence of skin lesions like cold sores or other symptoms. HSV-1 and HSV-2 infections can have different causes and presentations, so it's important to see a healthcare provider if you suspect infection or exposure.

Keep in mind that some people who have an HSV infection don't have any symptoms. Others may have a history of recurring infections that change how herpes is treated. You'll want to be sure that your testing is accurate by doing so at the right time in order to avoid false negative or false positive results.

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Sexually Transmitted Infections Treatment Guidelines, 2021.

  2. Lee R, Nair M. Diagnosis and Treatment of Herpes Simplex 1 Virus Infection in Pregnancy. Obstet Med. 2017;10(2):58-60. doi:10.1177/1753495X16689434

  3. Centers for Disease Control and Prevention. Genital herpes – CDC fact sheet.

  4. Vassantachart JM, Menter A. Recurrent lumbosacral herpes simplex virus infectionProc (Bayl Univ Med Cent). 2016;29(1):48–49. doi:10.1080/08998280.2016.11929356

  5. Whitley R, Kimberlin DW, Prober CG. Pathogenesis and disease. In: Arvin A, Campadelli-Fiume G, Mocarski E, et al., editors. Human Herpesviruses: Biology, Therapy, and Immunoprophylaxis. Cambridge: Cambridge University Press

  6. Labcorp. Herpes Simplex Virus (HSV) Types 1 and 2, NAA.

  7. Legoff J, Péré H, Bélec L. Diagnosis of genital herpes simplex virus infection in the clinical laboratory. Virol J. 2014;11:83. doi:10.1186/1743-422X-11-83

  8. Kimberlin DM. Immunotherapy of HSV infections – antibody delivery. In: Arvin A, Campadelli-Fiume G, Mocarski E, et al., editors. Human Herpesviruses: Biology, Therapy, and Immunoprophylaxis. Cambridge: Cambridge University Press

  9. Feltner C, Grodensky C, Ebel C, Middleton JC, Harris RP, Ashok M, et al. Serological Screening for Genital Herpes: An Evidence Review for the U.S. Preventive Services Task Force [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2016 Dec. Report No.: 15-05223-EF-1. PMID: 28079997.

  10. Allen UD, Robinson JL; Canadian Paediatric Society, Infectious Diseases and Immunization Committee. Prevention and management of neonatal herpes simplex virus infectionsPaediatr Child Health. 2014;19(4):201–212. doi:10.1093/pch/19.4.201

  11. Edgar NR, Saleh D, Miller RA. Recurrent Aphthous Stomatitis: A ReviewJ Clin Aesthet Dermatol. 2017;10(3):26–36.

  12. Yu X, Zheng H. Syphilitic Chancre of the Lips Transmitted by Kissing: A Case Report and Review of the LiteratureMedicine (Baltimore). 2016;95(14):e3303. doi:10.1097/MD.0000000000003303

  13. Hartwig S, St Guily JL, Dominiak-Felden G, Alemany L, de Sanjosé S. Estimation of the overall burden of cancers, precancerous lesions, and genital warts attributable to 9-valent HPV vaccine types in women and men in EuropeInfect Agent Cancer. 2017;12:19. doi:10.1186/s13027-017-0129-6

  14. Wagenlehner FM, Brockmeyer NH, Discher T, Friese K, Wichelhaus TA. The presentation, diagnosis, and treatment of sexually transmitted infections. Dtsch Aerzteb2016;113(1-2):11–22. doi:10.3238/arztebl.2016.0011

  15. Álvarez DM, Castillo E, Duarte LF, Arriagada J, Corrales N, Farias M, et alCurrent antivirals and novel botanical molecules interfering with herpes simplex virus infectionFront Microbiol. 2020;11:139. doi:10.3389/fmicb.2020.00139

  16. Centers for Disease Control and Prevention. Herpes – Genital (HSV) / Adolescents and Adults.

Additional Reading
Elizabeth Boskey, PhD

By Elizabeth Boskey, PhD
Elizabeth Boskey, PhD, MPH, CHES, is a social worker, adjunct lecturer, and expert writer in the field of sexually transmitted diseases.