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Is There a Herpes Blood Test?

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Updated February 03, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Question: Is There a Herpes Blood Test?
I recently received an e-mail containing the following question (paraphrased):
I live in a small town in the U.S., and I'm wondering if there is a blood test for herpes. My doctor said that he can only do a swab test, and he can't tell me if I have HSV-1 or HSV-2. I don't have sores, but I'm really curious as to whether or not I have herpes, since I know that you can be infected without anything showing.

It's unfortunate that doctors still aren't aware of the range of STD testing options available, because it is possible to screen people's blood for herpes antibodies -- even if the tests aren't perfect.

Answer:

Although the gold standard for herpes diagnosis is to do a viral culture or nucleic acid amplification test (NAT) from a visible sore, it is possible to screen for asymptomatic herpes infections using a blood test. There are a number of herpes blood tests out there and, although some doctors may be reluctant to use them, blood-based screening for herpes can be useful in a number of circumstances.

  • Monitoring the serostatus of a person whose sexual partner is infected with herpes (i.e. if they are part of a serodiscordant couple)

  • Learning whether you, and/or your potential partner, have herpes before starting a new relationship, so that you can make informed decisions about risk -- including whether or not suppressive therapy might be a valuable tool to reduce the risk of herpes transmission

  • Determining whether or not a known exposure to herpes has led to an infection

The reason that viral culture and NAT are the gold standard for herpes testing is that these tests look directly for the herpes virus. There is, therefore, a relatively low risk of false positives, which can be a serious concern with a disease as highly stigmatized as genital herpes.

In contrast, herpes blood tests look for antibodies to the herpes virus, and there is some possibility that these tests may detect antibodies to similar viruses that are cross-reacting to the tests -- thus leading to a person believing they have an asymptomatic herpes infection when they do not. The risk of getting such a false positive is related to the specificity of the particular herpes blood test being used and also to the prevalence of herpes in the population getting tested.

There are basically two sorts of blood tests for herpes -- type-specific tests and general herpes blood tests.

  • Type-specific herpes blood tests look for not only whether you have antibodies against a herpes virus but whether they are against HSV-1 or HSV-2.
     
    Note: Type specific testing will not tell you where you are infected with herpes since the "oral" herpes virus can infect the genitals, and vice versa.

  • General herpes blood tests look only for whether you have antibodies against any type of herpes. These blood tests are generally not recommended since they may carry a higher risk of false positives. Although I mention them here, if such a test is offered, you should request type-specific testing instead.

Should You Get a Herpes Blood Test?

There are many doctors and researchers who do not support widespread screening for genital herpes, since they believe that it's less important to identify asymptomatic infections than it is to eliminate the possibility of emotional damage from a false positive test. I personally disagree, both since it is possible to spread herpes infections in the absence of symptoms (something which many doctors fail to recognize) and since it is possible to have herpes symptoms and not realize they are caused by herpes. Therefore, I think that regular herpes screening can be a reasonable choice -- particularly for people who have multiple sexual partners or who enjoy casual sex.

That said, if your doctor is unable or unwilling to perform a blood test for herpes, and you want to get screened, I highly recommend visiting your local STD clinic. STD clinics often have better resources for comprehensive STD screening than doctors in private practice. However, since some areas have formal guidelines that recommend against generalized testing for herpes antibodies, you may need to argue for why it is important to you to receive a herpes blood test. A known exposure is generally considered an acceptable reason to want to be screened for herpes, even when the desire to inform yourself and your partner(s) is not.

Sources:

Biraro S, Mayaud P, Morrow RA, Grosskurth H, Weiss HA. Performance of commercial herpes simplex virus type-2 antibody tests using serum samples from Sub-Saharan Africa: a systematic review and meta-analysis. Sex Transm Dis. 2011 Feb;38(2):140-7.

Domeika M, Bashmakova M, Savicheva A, Kolomiec N, Sokolovskiy E, Hallen A, Unemo M, Ballard RC; Eastern European Network for Sexual and Reproductive Health (EE SRH Network). Guidelines for the laboratory diagnosis of genital herpes in eastern European countries. Euro Surveill. 2010 Nov 4;15(44). pii: 19703

Sheary B, Dayan L. Herpes simplex virus serology in an asymptomatic patient. Aust Fam Physician. 2005 Dec;34(12):1043-6.

Song B, Dwyer DE, Mindel A. HSV type specific serology in sexual health clinics: use, benefits, and who gets tested. Sex Transm Infect. 2004 Apr;80(2):113-7.

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