How Accurate are Herpes Blood Tests?

January 27, 2018

It can be incredibly trying to wonder if you’ve got herpes. That’s true whether you are worried because of symptoms, since you know you’ve just been exposed, or for any other reasons. One way to find out whether or not you have a genital herpes or oral herpes disease is to get a herpes blood test.

Nevertheless, many people have questions about how accurate herpes blood tests are.

The fact remains that herpes blood tests work pretty well, but no test is perfect. That is 1 reason doctors may be reluctant to check for herpes. They worry about balancing the patient’s desire to understand with the possible psychological damage caused by a positive herpes blood test result. Because of the stigma associated with herpes, that stress can be set up whether the result is true or false. 

Just how Accurate is a Herpes Blood Test?

It’s always possible for a test to give inaccurate results. The truth of a herpes blood test is dependent on two things. The first is how many people in the tested population have herpes. The second is which test was used. The sensitivity/specificity of 2 different, relatively standard, herpes blood tests are as follows:

  • ELISA:
    • ~91% sensitivity and 92% specificity for HSV-1
    • ~96% sensitivity and 97% specificity for HSV-2
  • Immunoblot:
    • ~99% sensitivity and 95 percent specificity for HSV-1
    • ~97% sensitivity and 98% specificity for HSV-2

    What does this mean for you?   That is where common herpes is comes to the calculation. It affects how likely positive tests and negative tests are to be correct. In reality, it can make a bigger difference than herpes blood test accuracy!

    Let’s make the reasonable assumption that approximately 50 percent of the people are infected with HSV1.

    That’s the virus primarily related to oral herpes and cold sores. It’s also associated with a rising amount of genital herpes infections. Then assume that 25% of people are infected with HSV2. That’s the virus primarily associated with genital herpes.  In that situation, the positive predictive value and negative predictive value are as follows:

    • ELISA:
      • HSV-1: Around 92% of positive evaluations give the proper outcome.
      • HSV-2: Around 92 percent of positive evaluations are right, and 98% of negative evaluations are right.
    • Immunoblot:
      • HSV1: Around 95% of favorable and 99 percent of unwanted evaluations are right.
      • HSV-2: Around 94% of positive and 99 percent of unwanted evaluations are correct.

    In conclusion, herpes blood tests are in fact pretty accurate. That is particularly true for the type specific tests which are most often recommended! In a comparatively large incidence people, they provide accurate results the vast bulk of the moment. It is worth noting, however, that if my incidence estimates were away, it might make a big difference. What when we worked from the premise that only 10% of the population was infected with virus? Then although almost all negative evaluations would continue to be true, positive tests would just be appropriate 55% to 85 percent of their time.

    In other words, there are a great deal of false positive tests.

    The possibility of false positive tests in populations where herpes isn’t common is a big concern. In reality, it is one reason that screening for herpes isn’t widely recommended. Doctors are worried that the stress of a false positive test may outweigh the advantages of early detection of the virus in someone who is asymptomatic.

    However, since herpes can be transmitted in the absence of symptoms and suppressive therapy can help prevent transmitting, I do not necessarily agree. Personally, I feel that people who know they’re in danger can make an educated decision to undergo a herpes blood test to be screened for the virus.

    That’s especially true when they are in a scenario where they might be exposing fresh sexual partners to the virus. It is, nevertheless, important to understand that false positive tests can occur. It’s also critical to be aware that, even if you’re infected with a herpes virus, living with herpes isn’t the end of the world.

    For your record? The centers for disease management currently estimate the incidence of herpes is pretty large. They estimate that by age 50, between 20 and 60% of adults are infected with HSV-2. There are big differences in prevalence that depend on race and sex.