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Cytomegalovirus (CMV) Antibody Test, IgG (Serum/Plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures the presence of Immunoglobulin G (IgG) antibodies to the cytomegalovirus (CMV), a common virus that can affect nearly everyone at some point in their lives.

Quick summary

["IgG antibodies indicate past infection or immunity to CMV."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
86517-0
Short code
CMV Ag Tiss Ql IF
Synonyms
CMV Ag Tiss Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Does This Test Measure?

The test detects IgG antibodies specific to CMV in your blood. IgG antibodies are part of your immune system’s long-term response to infections. If you have these antibodies, it suggests you’ve either had CMV in the past or are immune due to vaccination (though CMV vaccines do not exist).

Why Might You Need This Test?

Doctors may order this test to check for past CMV infection in people with weakened immune systems (e.g., after organ transplant, chemotherapy, or HIV), pregnant individuals to assess risk to the fetus, or those with symptoms like fatigue, fever, or organ-related issues that could be linked to CMV.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s analyzed to detect CMV-specific IgG antibodies using an immunoassay method.

What Are Common Results?

A positive result means IgG antibodies are present, indicating past infection or immunity. A negative result means no detectable IgG antibodies were found, suggesting no prior exposure or immunity. Results are not interpreted in isolation and should be reviewed by your healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

IgG antibodies to CMV are important for monitoring immunity in high-risk groups. For example, in immunocompromised patients, CMV can cause serious infections. In pregnancy, CMV is a concern because it can affect fetal development. This test helps guide treatment decisions or preventative measures.

Short name

CMV IgG Antibody

Frequently asked questions

What Does a Positive Result Mean?
A positive result means you likely had CMV at some point, but it does not indicate whether you’re currently infected. It also does not show the severity of your past infection. Your doctor may recommend further testing if needed.
Could I Have CMV Even If My Test Is Negative?
Yes, a negative IgG result means you currently do not have detectable IgG antibodies, but you may still be infected with CMV if you have active symptoms or a weakened immune system. Additional testing (like IgM or PCR) may be needed to check for current infection.
How Long Do CMV IgG Antibodies Last?
IgG antibodies to CMV typically remain in your system for life after infection, providing long-term immunity. However, if you’re immunocompromised, your body may not produce new antibodies if exposed again, and you could become susceptible to reactivation.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy