Overview of VZV IgG Test

• The test measures the presence and quantity of VZV IgG antibodies in the blood.
• A positive result indicates that a person has been previously exposed to the virus (either through past infection or vaccination) and has developed immunity.
• A negative result suggests no previous exposure or insufficient immunity.

Risk Assessment

This test is often performed to assess:

1. Immunity status: To determine whether someone has been vaccinated or previously infected, and therefore is protected from chickenpox or shingles.
   • Newborns and infants, especially those born to mothers who have had chickenpox or shingles, may be tested.
   • Pregnant women who have not had chickenpox or vaccination may need testing for immunity before pregnancy or during pregnancy.
   • Healthcare workers, to confirm if they have immunity before working with potentially exposed populations.
   • People exposed to VZV: If someone has been exposed to the virus, especially in an outbreak situation, the test can confirm immunity.

Normal Range

• • Negative: If the IgG level is below the threshold for positivity (e.g., < 0.9 IU/mL).
  • Positive: If the IgG level is above the threshold (e.g., > 1.1 IU/mL).
  • Equivocal: Results between the cut-off range (e.g., 0.9 - 1.0 IU/mL).

Interpretation of Results

1. Positive VZV IgG:

   • The person is immune, either from a previous infection or vaccination. No further action is typically needed.

2. Negative VZV IgG:

   • The person has no detectable antibodies, indicating no prior exposure or immunity. In this case, vaccination may be recommended, especially if the individual is at risk of exposure (e.g., healthcare workers, pregnant women).

3. Equivocal result:

   • The result is unclear and might require retesting or further diagnostic work-up.

Sample Type

• Blood sample: Typically, the test is conducted on a serum sample, which is collected from a venipuncture (blood draw).