Anti-SARS-CoV-2 Immunoglobulin G (IgG) Antibody, Serum
This test measures the level of Immunoglobulin G (IgG) antibodies in your blood that your immune system produces in response to exposure to the SARS-CoV-2 virus, which causes COVID-19.
["IgG antibodies help your body fight off the virus and provide long-term immunity after infection or vaccination."]
Key facts at a glance
- LOINC
- 22547-4
- Short code
- Deprecated S pneum19 IgG Ser-aCnc
- Synonyms
- Deprecated S pneum19 IgG Ser-aCnc
- Category
- coagulation
- 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?
IgG antibodies are a type of antibody produced by your immune system after you’ve been exposed to the virus. They can stay in your body for months or even years, helping to protect you from getting sick again. This test detects these antibodies in your serum, which is the liquid part of your blood after blood cells and clotting factors are removed.
Why Might You Need This Test?
Doctors may order this test to check if you’ve had a past infection with SARS-CoV-2, even if you didn’t experience symptoms. It can also help confirm if you’ve developed immunity after vaccination or natural infection. Some people may also have this test to monitor immune response over time.
How Is the Test Done?
A healthcare provider will draw blood from a vein in your arm. The blood sample is then sent to a lab, where it’s tested for the presence of IgG antibodies using an immunoassay method. This process usually takes a few days to complete.
What Are Possible Results?
A positive result means you likely had an infection with SARS-CoV-2 at some point or received a COVID-19 vaccine. A negative result suggests you either haven’t been exposed to the virus or your immune system hasn’t yet produced detectable antibodies. Results can vary based on when you were tested after exposure or vaccination.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
IgG antibody testing is important for understanding past exposure to COVID-19. Positive results can help guide decisions about travel, workplace safety, or participation in activities where exposure risk is a concern. It can also be useful in research, public health tracking, and assessing long-term immunity. However, it’s important to note that IgG alone doesn’t always indicate current infection—other tests may be needed for active virus detection.
Short name
IgG Antibody to COVID-19
Frequently asked questions
When Should I Expect Results?
What Does a Positive Result Mean?
Can I Get This Test at Home?
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