Varicella zoster virus (VZV) is a DNA virus of the Herpes group. It is one of eight herpes viruses known to infect humans. The virus causes a highly contagious but usually benign disease of children (usually under the age of 15) which is characterized by vesicular skin lesions (chicken pox). Symptoms include an uncomfortable itchy rash, fever, flu-like symptoms, and headache. Following primary infection, the virus remains latent in the body and can reactivate to cause herpes zoster (shingles), a syndrome of severe neuralgic pain in the intercostal or ophthalmic region or on the face. Symptoms of shingles include a mild to intense burning or itching pain in a band of skin at the waist, the face, or another location. Other symptoms such as fever, malaise, flu like symptoms including muscle aches, headache, swollen lymph nodes, and upset stomach might be experienced. Herpes zoster can lead to serious neurological complications (facial paralysis, sudden deafness, meningitis and polyneuritis). Infections are more symptomatic in adults and, in immunodeficient subjects (e.g. those with serious blood disorders or AIDS); the virus can disseminate and cause a potentially fatal hemorrhagic syndrome with diffuse intravascular coagulation, nodular pneumonia and meningoencephalitis. Primary infections with the varicella-zoster virus (i.e. chicken pox) in pregnant women should be closely monitored - infection of the embryo is actually rare but if it occurs it can result in scarring, atrophy of the limbs and sometimes under-development of the cortex. In utero infection later on in the term can lead to neonatal herpes zoster which is comparable to the disease seen in immunodeficient patients. This test is performed to confirm the diagnosis of active cases of chicken pox and shingles. IgG antibodies are produced by the body several weeks after the initial VZV infection to provide long-term protection. Levels of IgG RISE during the active infection then stabilize as the VZV infection resolves and the virus becomes inactive. Once a person has been exposed to VZV, they will have some measurable amount of VZV IgG antibody in their blood for the rest of their life. VZV IgG antibody testing can be used, along with IgM testing, to help confirm the presence of a recent or previous VZV infection.