SARS-CoV-2 Immunoglobulin M (IgM) Antibody Test, Serum/Plasma
This test detects antibodies (specifically IgM) your body produces in response to exposure to the SARS-CoV-2 virus, which causes COVID-19. IgM antibodies typically appear shortly after infection and can help confirm recent exposure.
["IgM antibodies signal recent infection; they appear early but decline over time."]
Key facts at a glance
- LOINC
- 94508-9
- Short code
- SARS-CoV-2 IgM SerPlBld Ql IA.rapid
- Synonyms
- SARS-CoV-2 IgM SerPlBld Ql IA.rapid
- 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-rapid
- 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?
The test measures the presence of Immunoglobulin M (IgM) antibodies against the SARS-CoV-2 virus in your serum or plasma. IgM is one type of antibody your immune system makes in response to infection. This test helps identify if you’ve been recently exposed to the virus that causes COVID-19.
Why Might You Need This Test?
Your healthcare provider may recommend this test if you suspect recent COVID-19 infection, especially if symptoms developed within the past few weeks. It can also be used as part of a diagnostic evaluation for suspected COVID-19, particularly when other tests are inconclusive or if symptoms are mild.
How Is This Test Performed?
A small blood sample is drawn from a vein in your arm. The blood is then processed to separate serum or plasma, which is tested for IgM antibodies using a specialized immunoassay method. Results are typically available within a few hours or the next business day.
What Do My Results Mean?
A positive result indicates the presence of IgM antibodies, suggesting recent exposure to the SARS-CoV-2 virus. A negative result means no detectable IgM antibodies were found at the time of testing. Interpretation should be done in conjunction with clinical symptoms, medical history, and other diagnostic tests.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Understanding IgM Antibodies in COVID-19
Short name
IgM Antibody Test for SARS-CoV-2
Frequently asked questions
IgM antibodies are produced early in the course of an infection and can appear within days to weeks after exposure. They are less long-lasting than other antibodies like IgG, which may persist longer. This test is useful for identifying recent infection but is not definitive for diagnosing COVID-19 alone. It should be used alongside clinical judgment and other diagnostic criteria, such as symptom assessment and, if applicable, a viral test.
IgM antibodies can begin appearing in your blood within about 7 to 10 days after exposure to the virus, but this can vary. Symptoms may also appear around this time. If you suspect recent exposure, it’s best to discuss timing with your healthcare provider.
IgM antibodies alone are not typically used to confirm past infection. Instead, IgG antibodies or combined IgM/IgG tests are often used for this purpose. IgM levels tend to decrease over time, so they may not be reliable for long-term infection confirmation.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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