OVERVIEW:
Varicella-zoster virus (VZV) is a member of the herpes virus family which causes two health problems chickenpox and shingles. Varicella-zoster virus tests detect either antibodies produced by the immune system in response to a VZV infection or detect the virus itself. Tests for chickenpox and shingles may be performed to detect and diagnose a current or past infection with VZV.
WHAT DOES THE TEST MEASURE?
This test looks for antibodies in the blood that the body makes against the varicella-zoster virus.
The varicella-zoster virus is very contagious. It can cause two health problems:
When the body becomes infected with the virus for the first time, it causes chickenpox. After having chickenpox, most people become immune to the virus for the rest of their life. They can't get chickenpox again.
But after the first illness, the virus becomes dormant and "hides" in the body. Later in life, the virus can become active again. It causes a painful rash called shingles, or herpes zoster.
Q1. How is the test performed?
A blood sample is obtained from a vein.
Q2. Is there any risk associated with this test?
There is no significant risk associated with this test, however, in rare cases, a patient may develop a clot or hematoma around the site of the needle prick. Other complications include nausea, vomiting, diarrhea.
Q3. What might affect the test results?
A history of chickenpox or vaccine against the disease can affect the results.
INTERPRETATION OF THE RESULT:
When someone is exposed to the Varicella-zoster virus, the person's immune system responds by producing antibodies to the virus. Laboratory tests can detect and measure the level of VZV IgG antibodies in the blood:
IgG antibodies are produced by the body a few weeks after the initial Varicella-zoster virus infection and provide long-term protection. Levels of IgG rise during the active infection, then stabilize as the VZV infection resolves and the virus becomes inactive.
Why get tested?
To diagnose a current or past case of chickenpox or shingles. If the symptoms of chickenpox are visible, the symptoms are as follows:
- Fever
- Headache
- Sore throat
- Distinctive rash around the body a day or two after other symptoms begin
