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Cytomegalovirus Antibody, IgM (Serum)

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

This test measures the presence of Immunoglobulin M (IgM) antibodies against cytomegalovirus (CMV) in your blood. IgM antibodies appear shortly after infection and can help identify recent CMV exposure.

Quick summary

["IgM antibodies to CMV may signal an active infection, often useful in diagnosing recent or acute CMV exposure."]

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

Key facts at a glance

LOINC
109960-5
Short code
CMV Ab Msmt Ser
Synonyms
CMV Ab Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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?

IgM antibodies are a type of immune protein your body produces in response to a recent infection. In this test, we detect whether your serum contains these antibodies against CMV, a common virus that can affect many organs, especially in people with weakened immune systems.

Why Might You Need This Test?

Doctors may order this test if you have symptoms like fever, fatigue, or organ-related issues (such as vision changes or swelling) that could suggest CMV infection. It’s also used in pregnant women or people with immune conditions to monitor potential risks.

When Might You Get Results Back?

Results are typically ready within 3–5 business days, depending on lab processing times. Your healthcare provider will discuss the meaning with you based on your symptoms and medical history.

What Does a Positive Result Mean?

A positive IgM result strongly suggests recent CMV infection. However, false positives can occur, so follow-up testing or additional evaluation may be needed to confirm diagnosis and guide treatment.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CMV IgM Antibody

Frequently asked questions

How long will it take to see if my results are abnormal?
IgM results alone don’t provide a numeric range, but a positive result indicates recent infection. Your doctor will assess this alongside symptoms, medical history, and other tests (like IgG antibodies) to determine next steps.
Can I have false positives or negatives with this test?
Yes, IgM tests can sometimes give false positives due to cross-reactions or past infections. False negatives may occur if the infection was recent or if your immune system is suppressed. Your doctor will interpret results in context.
What if my test is positive but I don’t have symptoms?
A positive IgM result without symptoms could mean recent exposure, but further testing (like IgG antibodies) or clinical evaluation is needed. Some people may not show symptoms even with infection.
  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