How Accurate is the Herpes Blood Test?

[nmo27]

A few days ago, I went to Planned Parenthood for what was diagnosed as a first outbreak of genital herpes- though we're still waiting on results for the swab test. I asked the doctor/nurse practitioner who examined me what I could advise the partners could do to determine their status and she said that Planned Parenthood did not even use the herpes blood test because it came back with too many false positives and false negatives and that I should advise them to "be careful" and get a swab test if they noticed any sores.

 

This seems like highly impractical, even dangerous advice, as so many people with herpes remain asymptomatic but still shed the virus.

 

How accurate is the blood test? Or where might you suggest I look for a reliable source of information on this matter? My internet searches so far have not lead me to any definitive answers.

[CanadianGuy2012]

Hey my province in Canada does not do ANY blood testing for herpes! They say it doesn't tell you where the virus is, is not accurate, and is not worth anything to the health system considering how expensive it is. I have to drive to the US to get a proper test.

 

That's bullshit tho, tests like the Quest Herpesselect are very accurate (95%+), although if you score between 1 and 5 without ever having a positive swab it's not considered definitive. If you score above 1 and you get a positive swab you're considered positively positive.

[nmo27]

Thanks for the info- can you recommend any good sources with accurate information on the tests, and that further explain how the scoring systems work on the test you mentioned?

[healing]

On the tests I took, my score is considered low and I have never had any symptom, so it might be a false positive. I am planning to take the Western Blot Test which will determine with certainty whether or not I have HSV2.

[mr_hopp]

Yes, I've been reading up on this as well after an enlightening chat with a fellow member of this site and then a scientist at the virology research clinic at the University of Washington. The Western Blot measures 14 peptides vs. the IgG test's 2 ... I've heard that the IgG test 97% accurate while the Western Blot is 99.9%. Sometimes the IgG test misses actual herpes infections that the Blot will find due to measuring more peptides. Looking deeper into this, but this is what initial findings point to ... Keep us updated on what you find out!

[nmo27]

This http://www.racoon.com/herpes/WB_test.htm makes it look like the western blot can be a little tricky and expensive to obtain. Is the lab at the University of Washington really the only one that performs this test?

 

healing, is your healthcare provider taking care of the blood work for you, or do you have to ship it to the lab yourself?

 

Interesting information, thanks H_Opp, and let me know if you find anything more!

[Shannon (SingBlueSilver)]

When I got diagnosed from a swab, the doctor said they rarely do bloodtests as they are so inaccurate and also, most people have the antibody. She even went so far as to say that if there's no outbreak, what does it matter what the blood test says because it is so widespread and the test isn't accurate so just assume you have it and take precautions. Then I cried and she said it wasn't such a big deal. I saw another doctor and her thought about the blood test was the same, if you don't have outbreak, don't worry. That's the message I got. I think it's all BS. Of course we want the blood work to tell us what we have and be sure we have it. Weirdly, I have HSV 1 on my genitals and I had to force them to give me the blood test. AND more importantly, if you ask for a STD test, it doesn't include a HSV test!!! You have to ask for it! I think this is really an injustice to people who think we are safe.

[LionEagle]

Blood tests can be used when a person has no visible symptoms but has concerns about having herpes. Blood tests do not actually detect the virus; instead, they look for antibodies (the body's immune response) in the blood.

 

IgM vs. IgG When an individual contracts herpes, the immune system responds by developing antibodies to fight the virus: IgG and IgM. Blood tests can look for and detect these antibodies, as the virus itself is not in blood. IgG appears soon after infection and stays in the blood for life. IgM is actually the first antibody that appears after infection, but it may disappear thereafter.

 

IgM tests are not recommended because of three serious problems:

 

1. Many assume that if a test discovers IgM, they have recently acquired herpes. However, research shows that IgM can reappear in blood tests in up to a third of people during recurrences, while it will be negative in up to half of persons who recently acquired herpes but have culture-document first episodes. Therefore, IgM tests can lead to deceptive test results, as well as false assumptions about how and when a person actually acquired HSV. For this reason, we do not recommend using blood tests as a way to determine how long a person has had herpes. Unfortunately, most people who are diagnosed will not be able to determine how long they have had the infection (see reference 1).

 

2. In addition, IgM tests cannot accurately distinguish between HSV-1 and HSV-2 antibodies, and thus very easily provide a false positive result for HSV-2. This is important in that most of the adult population in the U.S. already has antibodies to HSV-1, the primary cause of oral herpes. A person who only has HSV-1 may receive a false positive for HSV-2.

 

3. IgM tests sometimes cross-react with other viruses in the same family, such as varicella zoster virus (VZV) which causes chickenpox or cytomegalovirus (CMV) which causes mono, meaning that positive results may be misleading.

 

The accurate herpes blood tests detect IgG antibodies. Unlike IgM, IgG antibodies can be accurately broken down to either HSV-1 or HSV-2. A recent study corroborates this finding: labs that used non-gG-based tests for herpes had high false-positive rates for HSV-2 antibodies (14-88% saying the blood sample was positive for HSV-2) in samples that were actually only positive for HSV-1 antibodies. But 100% of the labs using gG-based tests accurately reported that the blood sample was negative for HSV-2 (see reference 2).

 

The challenge here is that the time it takes for IgG antibodies to reach detectable levels can vary from person to person. For one person, it could take just a few weeks, while it could ta ke a few months for another. So even with the accurate tests, a person could receive a false negative if the test is taken too soon after contracting the virus. For the most accurate test result, it is recommended to wait 12 - 16 weeks from the last possible date of exposure before getting an accurate, type-specific blood test in order to allow enough time for antibodies to reach detectable levels.

 

There are currently several FDA-approved, gG-based blood tests that can give accurate results for herpes. Like any blood test, these tests cannot determine whether the site of infection is oral or genital. However, since most cases of genital herpes are caused by HSV-2, a positive result for type-2 antibodies most likely indicates genital herpes.

 

It may be necessary to request on of these tests by name from your healthcare provider. ASHA has created a quick reference guide to herpes blood tests, including a chart that outlines and compares the accurate, FDA-approved type-specific blood tests available for herpes simplex antibodies. To determine which test might be best for your situation - or to show your doctor which tests are available (since herpes is not routinely included in STD screenings), you can download and print ASHA's Herpes Blood Test Guide.

 

For healthcare providers, we've developed the Herpes Testing Toolkit, which was reviewed by leading experts in this field. The resource explains the increasing role of type-specific herpes serologic assays, presents clinical scenarios in which serologic testing are beneficial, and reviews key factors in a differential diagnosis for genital herpes. To order a copy of the Herpes Testing Toolkit, visit the ASHA online store. Providers can also access the online version of the Herpes Testing Toolkit on the ASHA website.

 

References 1. Ashley RL. Performance and use of HSV type-specific serology test kits. HERPES 2002;9(2):38-45. 2. Ashley Morrow R, Brown ZA. Common use of inaccurate antibody assays to identify infection status with herpes simplex virus type 2. Am J Obstet Gynecol 2005;193:361-2

 

Taken from the ASHA website - http://www.ashastd.org

 

LE

[nmo27]

Thanks so much LionEagle, that was exactly the information I was looking for!

[Serpere]

Herpes IgG tests are one type of blood test for the herpes simplex virus (HSV). Herpes blood tests, including the herpes IgG test, look for the body's immune reaction to a herpes infection. They don't search directly for the virus. Because the immune reaction takes time to develop after the time of infection, it's not immediately detectable.

Results for a herpes test will usually be back within a week. In general, the results will be reported as positive, negative, or equivocal. A positive test means that IgG was detected. An equivocal test means that the results were unclear. 

Hope this helps. 
Pat