Varicella Immunity Test

Authored By: Dr. Jana Lim
Last updated: Jul 3, 2025

A varicella immunity test is a serological blood test used to find out whether you are protected against the varicella zoster virus, which causes chickenpox and shingles. It is often recommended if your immunity status is unclear and confirmation is needed for medical, occupational, or personal reasons.

This test is commonly used for individuals who are unsure whether they have had chickenpox before or received the vaccine. It may also be considered if you were vaccinated many years ago, as immunity from the vaccine can decrease over time in some people.

The varicella immunity test works by detecting varicella zoster virus (VZV) IgG antibodies in the blood through laboratory testing. IgG, which stands for immunoglobulin G, is a type of antibody produced by your immune system in response to a past infection or vaccination.

If these antibodies are present in your blood, it usually means you have developed immunity and are less likely to become infected again.

You may consider a varicella immunity test if you are unsure whether you are protected against chickenpox and need confirmation for reasons such as:

1. Adults planning to receive the varicella vaccine, to avoid unnecessary vaccination if they are already immune.
2. Individuals born outside Singapore, especially from countries where varicella vaccination is not part of the routine childhood immunisation schedule.
3. Healthcare workers and caregivers, who may be at risk of exposing vulnerable patients to the virus.
4. Individuals planning for pregnancy who are unsure if they have had chickenpox or the vaccine, as infection during pregnancy can lead to complications.
5. People with weakened immune systems, such as those undergoing chemotherapy or organ transplant, who may have more severe illness if infected.

If you are unsure, it is best to consult a doctor who can determine if the test is necessary based on your health history and current situation.

Results from a varicella immunity test are typically reported as positive, negative, or equivocal:

• Positive (IgG detected) – You are likely immune, either from a previous infection or vaccination.
• Negative (IgG not detected) – You are likely not immune and may be at risk of infection. Your doctor may recommend vaccination or further evaluation.
• Equivocal Result – The result is inconclusive, and your doctor may advise retesting or vaccination depending on your situation.

Your doctor will interpret your test results together with your medical history and vaccination records.

At ATA Medical, we offer varicella immunity testing along with a range of related tests and vaccinations. Prices are as follows:

A blood test at our clinic typically takes 30 to 60 minutes during off-peak periods. Results are usually available within 3 to 5 days, and your doctor will call or email you to discuss the findings.

No special preparation is needed for a varicella immunity test. You can eat and drink as usual before your appointment, and there is no need to fast.

If you are unwell or taking medications that may affect your immune response, inform your doctor beforehand so they can advise whether the timing of the test should be adjusted.