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Human Herpesvirus 6 Immunoglobulin M (IgM) Antibody, Serum

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

This test measures the presence of Immunoglobulin M (IgM) antibodies against Human Herpesvirus 6 (HHV-6) in your blood. IgM antibodies are typically produced shortly after infection begins.

Quick summary

["IgM antibodies can help identify recent HHV-6 infection."]

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

Key facts at a glance

LOINC
110966-9
Short code
HHV6 IgM Msmt Ser
Synonyms
HHV6 IgM 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
CPT
82784
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 antibody your immune system produces in response to an infection. In this test, we check for IgM antibodies specifically against HHV-6, a virus that can cause infections, including fever and rash. These antibodies usually appear within a few weeks after infection but can decline over time as your body produces other types of antibodies.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like fever, rash, or other signs of infection that could be linked to HHV-6. It can also be used to monitor certain conditions, such as immune system responses in people with weakened immunity.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood, similar to other routine blood tests. The process usually takes a few minutes.

What Are the Possible Results?

A positive result for IgM antibodies suggests recent infection with HHV-6. A negative result means you likely do not have recent infection, but it doesn’t rule out past exposure. Results should always be interpreted by your healthcare provider in the context of your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

IgM antibodies to HHV-6 are useful for diagnosing recent infections. They can help confirm if an illness is caused by HHV-6, especially in cases where symptoms like fever, fatigue, or rash are present. However, IgM levels can decrease over time, so follow-up testing may be needed if symptoms persist or recur.

Short name

IgM Antibody to HHV-6

Frequently asked questions

What does a positive IgM result mean?
A positive IgM result indicates that you likely had an active HHV-6 infection within the past few months. This could mean you recently caught the virus, which may have caused symptoms like fever, fatigue, or a rash. It does not necessarily mean you will have ongoing issues, but your healthcare provider may recommend further evaluation or monitoring.
Can this test detect past infection?
No, this test specifically measures IgM antibodies, which are produced during a recent infection. To detect past infection, other tests that measure different types of antibodies (such as IgG) would be needed.
Is there any risk or discomfort from this test?
There is a small risk of mild discomfort or bruising at the injection site, similar to other blood tests. Most people experience minimal or no pain. If you have a bleeding disorder or are on blood-thinning medication, let your healthcare provider know before the test.
  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