What does a Varicella-Zoster Virus (VZV) antibody (AB) Immunoglobulin G (IgG) Enzyme Immunoassay (EIA) result of less than 1.00 indicate?

VZV IgG <1.00: Interpretation

A VZV IgG EIA result of <1.00 indicates you are seronegative for varicella-zoster virus, meaning you lack immunity to chickenpox and should receive varicella vaccination if you are a candidate. 1

What This Result Means

• You are considered susceptible to varicella (chickenpox) infection with a result below the threshold of 1.00, which is the standard cutoff for determining immunity in most commercial EIA assays 2
• This negative result indicates you have neither had chickenpox nor developed adequate antibody response from previous vaccination 1
• The cutoff value of 1.00 has been statistically established to distinguish between immune and susceptible populations in VZV IgG enzyme immunoassays 2

Clinical Implications for Management

• You should receive varicella vaccination (two doses spaced 4-8 weeks apart) unless you have contraindications, as you lack protective immunity 3
• If you are a healthcare worker or in another high-risk occupation, vaccination is particularly important to prevent occupational exposure and transmission 3
• If exposed to someone with chickenpox or shingles, you may be a candidate for Varicella Zoster Immune Globulin (VZIG) within 10 days of exposure if you are immunocompromised or pregnant 1, 4
• Post-exposure prophylaxis with varicella vaccine can be considered within 3-5 days of exposure if you are not immunocompromised 1

Important Caveats About Testing

• If you previously received varicella vaccine, this negative result may not accurately reflect your true immunity status because commercial EIA tests have reduced sensitivity (46-89%) for detecting vaccine-induced antibodies compared to natural infection 3, 5
• The CDC does not recommend routine serologic testing after vaccination due to these test limitations 1
• If you have a reliable history of chickenpox disease or documented receipt of two doses of varicella vaccine, you should be considered immune regardless of antibody test results 1

Next Steps

• Proceed with varicella vaccination if you have no documented history of chickenpox or vaccination 1
• After completing the two-dose vaccine series, you do not need repeat antibody testing to confirm immunity 1
• Avoid contact with pregnant women, newborns, and immunocompromised individuals if you develop a vaccine-related rash (occurs in 3-5% of vaccinees) 6