What is the Varicella Zoster IgM Antibodies test?

The Varicella Zoster IgM Antibodies test measures IgM antibodies produced by the immune system shortly after exposure to the varicella zoster virus (VZV). IgM antibodies are typically associated with recent or active infection.

This test is mainly used to support the diagnosis of acute chickenpox or, less commonly, recent shingles, particularly when symptoms are unclear or when PCR testing is not available. IgM antibodies usually appear early and decline over weeks.

Results must be interpreted carefully and in combination with symptoms and, where appropriate, other tests such as PCR or IgG antibodies.

Why do I need a Varicella Zoster IgM Antibodies test?

Identifying recent infection is important in clinical decision-making, especially in higher-risk individuals.

You may need this test if you:

• Have a recent onset of rash or blistering
• Have symptoms suggestive of chickenpox
• Are pregnant with suspected recent exposure
• Are immunocompromised with unclear symptoms
• Need to assess recent infection rather than immunity
• Have inconclusive PCR or clinical findings

The test helps support whether symptoms are linked to a recent VZV infection.

Benefits of the test

1. Supports diagnosis of recent infection
   Detects early immune response to VZV.
2. Useful when PCR is not performed
   Provides serological evidence of recent exposure.
3. Helps differentiate recent from past infection
   Complements IgG testing.
4. Important in pregnancy assessment
   Supports evaluation of recent exposure.
5. Simple blood-based testing
   Requires only one blood sample.
6. Widely used in clinical practice
   Standard serology marker for acute infection.
7. Supports clinical decision-making
   Helps guide further investigations.
8. Adds clarity in atypical cases
   Useful when symptoms are unclear.

Step-by-step: How we offer testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic
• Attend your appointment
• Blood sample taken by a clinician
• Sample sent to the laboratory
• Results are issued once analysis is complete

Home or hotel visit (+£60, UK-wide)

• Mobile phlebotomist attends your location
• Blood sample taken at home or hotel
• No clinic visit required
• Sample securely transported to the laboratory

Your results explained

Negative IgM

• No detectable IgM antibodies
• UK standard: Negative
• Suggests no evidence of recent infection

Positive IgM

• IgM antibodies detected
• UK standard: Positive
• Suggests recent or current varicella zoster infection

False positives and prolonged IgM positivity can occur; results should be interpreted with clinical context and other tests.