Cytomegalovirus (IgG/IgM) Antibodies

What is the Cytomegalovirus (IgG/IgM) antibody test?

The Cytomegalovirus (CMV) IgG/IgM antibody test is a blood test that measures two types of antibodies produced in response to CMV infection. IgM antibodies indicate a recent or active infection, while IgG antibodies suggest past exposure or immunity.

CMV is a common virus belonging to the herpesvirus family. Once infected, the virus remains dormant in the body and may reactivate later, particularly in individuals with weakened immune systems.

This test is widely used in pregnancy screening, transplant medicine, and immunology to assess infection status and potential clinical risk.

Why do I need a Cytomegalovirus antibody test?

CMV infection is often mild or asymptomatic in healthy adults but can be serious in certain groups, including pregnant women, newborns, and immunocompromised individuals.

Testing helps determine whether an infection is recent, past, or absent, which is essential for clinical decision-making and risk assessment.

You may need a CMV IgG/IgM test if you:

• Are pregnant or planning pregnancy
• Have had close contact with young children
• Have unexplained flu-like symptoms
• Experience prolonged fatigue or fever
• Have a weakened immune system
• Are undergoing fertility treatment
• Are a transplant donor or recipient
• Have abnormal liver function tests
• Need clarification of past CMV exposure

Benefits of the Cytomegalovirus (IgG/IgM) test

• Identifies current or recent infection
  IgM antibodies help detect active CMV infection.
• Confirms past exposure or immunity
  IgG antibodies indicate previous infection.
• Essential in pregnancy screening
  Helps assess risk of congenital CMV.
• Supports immune health assessment
  Relevant for immunocompromised patients.
• Guides clinical monitoring
  Supports follow-up and treatment decisions.
• Simple and reliable blood test
  Requires only a single blood sample.
• Used in fertility and transplant care
  Important for donor and recipient screening.
• Helps explain unexplained viral symptoms
  Useful when routine tests are inconclusive.

Step by step – how the test works

You can access CMV testing UK-wide through two options:

1. Clinic appointment
   Choose your nearest UK clinic, where a healthcare professional will take your blood sample.
2. At-home or hotel visit (£60 extra)
   A qualified phlebotomist visits your home or hotel, so you don’t need to travel.

Your sample is analysed in a UK laboratory, and results are delivered securely.

Your results explained

Negative IgG & IgM (No antibodies detected)

Indicates no evidence of past or current CMV infection. You may be susceptible to future infection.

Typical UK interpretation:

• IgG: Negative
• IgM: Negative

Positive IgM (Recent or active infection)

Suggests a recent or current CMV infection. Further monitoring or repeat testing may be required.

Typical UK interpretation:

• IgM: Positive
• IgG: Negative or low

Positive IgG (Past infection)

Indicates previous exposure to CMV. The virus remains dormant but is usually not clinically significant in healthy individuals.

Typical UK interpretation:

• IgG: Positive
• IgM: Negative

Results must always be interpreted alongside symptoms and clinical context.