Chickenpox, Herpes Zoster Antibodies, Shingles, Varicella-Zoster Antibody Screen, Qualitative, Varicella-Zoster Immune Status, VZ Ab, IgG, VZV, Varicella-Zoster IgG, Serum
Determination of immune status of individuals to the varicella-zoster virus (VZV)
Documentation of previous infection with VZV in an individual without a previous record of immunization to VZV
IgG-class antibodies to varicella-zoster virus may be present in serum specimens from individuals who have received blood products within the past several months but have not been immunized or experienced past infection with this virus.
Serum specimens drawn early during acute phase of infection may be negative for IgG-class antibodies to this virus.
Vaccinated: Positive (> or =1.1 AI)
Unvaccinated: Negative (< or =0.8 AI)
Reference values apply to all ages.
Positive: Antibody index (AI) value of 1.1 or higher:
The reported AI value is for reference only. This is a qualitative test and the numeric value of the AI is not indicative of the amount of antibody present. AI values above the manufacturer recommended cutoff for this assay indicate that specific antibodies were detected, suggesting prior exposure or vaccination. The presence of detectable IgG-class antibodies indicates prior exposure to the varicella-zoster virus (VZV) through infection or immunization. Individuals testing positive are considered immune to varicella-zoster.
Equivocal: AI 0.9-1.0
Submit an additional specimen for testing in 10 to 14 days to demonstrate IgG seroconversion if recently vaccinated or if otherwise clinically indicated.
Negative: AI of 0.8 or lower
The absence of detectable IgG-class antibodies suggests no prior exposure to the VZV or the lack of a specific immune response to immunization.