What is Herpes?
It is a common viral infection caused by herpes simplex virus (HSV). Its 2 types present include HSV-1 & HSV-2. Both viruses are known to be contagious (transmissible) and cause sores or blisters around the mouth or genitals with other symptoms too. The HSV-1 is known to cause oral herpes which will affect mouth & surrounding skin and can spread via contact with moist skin of infected mouth. While HSV-2 is known to cause genital herpes i.e. sores develop on penis, around or inside vagina, buttocks, or on anus. HSV-2 can be sexually transmitted. It may also be transmitted from a genital herpes mother to her baby while giving birth.
What is Herpes IgG Lab Test?
For the detection/diagnosis of HSV infection, an immunoglobulin G (IgG) blood test is performed. This test looks for antibodies (& not the virus) which are produced by the body in response to viral infection. Specific HSV IgG will develop in the body when HSV infection occurs. IgG antibodies are known to develop after several weeks (4 to 6) of exposure & stay in the body for lifetime providing immunity against infection.
Why is Herpes IgG Lab Test done?
This test is performed for the purpose of:
- Confirming a genital herpes infection and not recommended as a general screening test.
- This test is mostly done on pregnant women who are at risks of having genital herpes which reduces chances of virus transmission to the baby.
- Its advantage is that IgG test can differentiate better among HSV-1 & HSV-2 as compared to IgM (immunoglobulin M) test.
- HSV IgG test done early during infection is helpful in determining whether you have been exposed to HSV-1 or HSV-2 infection. However, if signs of infection are present but the test comes negative that means you have a new infection & were never exposed to the virus before.
- What do you mean by HSV IgG positive?
This result means that antibody is present & you have had HSV infection in the past.
- Do IgG blood tests show accuracy in detecting herpes?
Yes, accurate herpes blood tests detect IgG antibodies as IgG antibodies can be accurately broken to either HSV-1 or HSV-2 (the type of antibody detected shows the type of HSV infection present). However, IgG reaching detectable levels varies from person to person
- How long will it take for HSV IgG to stay positive?
Time taken for development of IgG antibodies in detectable levels following HSV infection may be 21 to over 42 days & may probably last for lifetime.
- What is meant if you say IgG is high?
Immunoglobulin G levels become high if you have had a long-term (chronic) infection like in HIV. Their levels may also rise during IgG multiple myeloma, multiple sclerosis & long-term hepatitis.
- What are normal ranges of IgG?
Adult normal IgG antibody range is from 6.0 to 16.0 g/L.
HSV IgG antibodies take about four to six weeks after suspected exposure to become visible at detectable levels.
INTERPRETATION OF THE RESULTS:
- "Positive" HSV-1 or HSV-2 IgG: indicates that antibodies are present in blood & you've had herpes infection in the past even if you didn't notice the signs.
- "Negative" HSV IgG: indicates that you are unlikely to have had HSV infection or your body has not yet produced enough HSV antibodies.
- "Equivocal" IgG: indicates unclear results. Doctors might recommend other tests (culture or PCR) or to repeat this same test after a few weeks.
The test simply takes place to detect & diagnose infection caused by herpes simplex virus (HSV).