What Does a Positive Herpes IgG Test Mean?

August 25, 2018

Herpes IgG evaluations are just one type of blood test for the herpes simplex virus (HSV).  Herpes blood tests search for the human body’s immune reaction to a herpes infection. They do not search directly for the virus. Because the immune reaction takes time to grow after the time of infection, it is not immediately detectable. In fact, depending on the kind of evaluation used, it may take around four weeks to turn into positive within an HSV IgG test.

Hint: If you’ve got herpes symptoms, visit the doctor straight away. Sores can be tested directly. You don’t have to wait for the immune system to respond. This type of testing could be more precise if the sore is analyzed fast enough. 

How the Test Works

When a person gets infected, the immune system attempts to fight off the infection. That’s true not just for herpes but for almost any pathogen, Part of the procedure involves the production of antibodies. These proteins are unique for every infection they’re fighting.

To get a new type of disease, it requires some time for your body to make antibodies.  The body is able to make several kinds of antibodies to fight infections. The two forms that herpes blood tests look like are IgG and IgM. Herpes IgM antibodies are modulated by herpes blood tests over 7-10 days after initial infection. IgM levels stay high for around two weeks. After that, they usually decline.

Hence IgM testing is primarily considered to be useful for detecting acute infection. However antibody levels also occasionally go up through an outbreak.

In contrast, HSV IgG antibodies do not appear till slightly later after first infection. A positive herpes IgG test, if the test result is true, means that your body has been infected with the herpes simplex virus.

What’s more, type specific HSV IgG tests may be used to distinguish between HSV-1 and HSV-2. Type-specific evaluations are far more accurate than non-type-specific​ tests, but they can not detect whether a specific disease is oral or genital. The only way to ascertain that would be to watch for symptoms. 

HSV-1 usually infects the mouth, causing oral herpes, and HSV-2 usually infects the genitals. But, there are a growing number of individuals with genital HSV-1.   That is why herpes IgG and IgM tests can only tell you that you have been infected. They can not show where.

Test Results & Period of Infection

Should you test positive for HSV IgG but not IgM, then your herpes infection is most likely not recent. You’ve likely been infected for at least 2 months. Individuals with newer illnesses are more likely to test positive for both herpes IgG and IgM. They could also be positive for herpes IgM. The conversation, however, isn’t true. Positive herpes IgG and IgM results collectively do not necessarily mean you’re infected recently. Between 30 and 70 percent of individuals with recurrent herpes infections can test positive for herpes IgM.

Evaluation Results and Timing of Infection
   Favorable IgG Negative IgG
Positive IgM  Infection date indeterminate  Acute/Recent infection
Negative IgM  Established Infection  No infection detected

Exam Truth

It’s possible to have a false positive or false negative outcome. That’s true for a HSV IgG or HSV IgM test. Thus, don’t panic if your herpes blood test results do not agree with your known risk factors and sexual history. Instead, talk to your physician about possible issues with analyzing. Diagnostic testing isn’t perfect. You also might not be accurately assessing your risk. Many people do not understand that herpes could be transmitted even if their partner has no symptoms or doesn’t know they are infected.