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SARS-CoV-2 Immunoglobulin M (IgM) Antibody Test, Serum/Plasma

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

This test detects antibodies (specifically IgM) produced by your immune system in response to exposure to the SARS-CoV-2 virus, which causes COVID-19. IgM antibodies typically appear shortly after infection but decline over time.

Quick summary

["IgM antibodies help identify recent infection and can support diagnosis when combined with other tests."]

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

Key facts at a glance

LOINC
94506-3
Short code
SARS-CoV-2 IgM SerPl IA-aCnc
Synonyms
SARS-CoV-2 IgM SerPl IA-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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?

This test measures the presence of IgM antibodies against SARS-CoV-2 in your blood. IgM is one type of antibody your body produces early in an infection to fight the virus. The test uses a specialized immunoassay method to detect these antibodies in serum or plasma samples.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms of COVID-19 (such as fever, cough, or shortness of breath) or if you’ve been exposed to someone with COVID-19. It can also be used to monitor recovery or assess recent exposure, especially in certain clinical settings.

When Might Results Be Useful?

IgM antibodies often appear within 1–2 weeks after infection and can remain detectable for several months. They are useful for identifying recent exposure, particularly when combined with clinical symptoms or other diagnostic tests. However, IgM alone may not confirm past infection if other antibodies (like IgG) are also present.

What Does a Positive Result Mean?

A positive result indicates the presence of IgM antibodies, suggesting you may have been infected with SARS-CoV-2 recently. This does not definitively confirm a current infection, as IgM levels can vary and may not be present in all cases. Always discuss results with your healthcare provider for interpretation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Understanding IgM in COVID-19 Testing

Short name

IgM Antibody to SARS-CoV-2

Frequently asked questions

When could I expect to get this test?
This test is typically ordered by your doctor or healthcare provider based on your symptoms, exposure history, or other clinical needs. They may schedule it during an evaluation for suspected COVID-19 or as part of ongoing monitoring. Timing can vary, so follow their guidance.
What are the limitations of this test?
IgM tests are not definitive for diagnosing active COVID-19, as they may be negative even if you’re infected. They can also be affected by recent vaccinations or prior infections, which may produce IgM antibodies. False positives or negatives are possible, so results should be interpreted alongside clinical findings and other tests.
How long will it take to get my results?
Results may be available within 24–72 hours, depending on your lab’s processing time. Your healthcare provider will contact you directly with the outcome once it’s ready. Always confirm with them about next steps.
  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