Reference ranges for all ages:

– Vaccinated: positive (> or =1.1 AI)

– Unvaccinated: negative (< or =0.8 AI)

A positive IgG result indicates the presence of antibodies to varicella zoster virus.

– The test cannot distinguish between past infection and current infection though, so a positive result could indicate active infection and not immunity.

– If active infection is not suspected based on your history, clinical presentation, and other laboratory results, then a positive IgG result is likely due to past infection. In such a case, the patient is presumed to be immune to varicella zoster virus.

Positive IgG and positive IgM:

A positive IgG result coupled with a positive IgM result suggests recent infection with varicella-zoster virus (VZV). This result should not be used alone to diagnose VZV infection and should be interpreted in the context of clinical presentation.

Positive IgG and negative IgM:

A positive IgG result coupled with a negative IgM result indicates previous vaccination to or infection with VZV. These individuals are considered to have protective immunity to reinfection.

Negative IgG and negative IgM:

A negative IgG result coupled with a negative IgM result indicates the absence of prior exposure to VZV and non immunity. However, a negative result does not rule-out VZV infection. The specimen may have been drawn before the appearance of detectable antibodies. Negative results in suspected early VZV infections should be followed by testing a new serum specimen in 2 to 3 weeks.