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
- 30492-3
- Short code
- Deprecated S pneum19 IgG sp1 Ser-mCnc
- Synonyms
- Deprecated S pneum19 IgG sp1 Ser-mCnc
- 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 protein your immune system creates to recognize and fight the SARS-CoV-2 virus. After you’ve been exposed to the virus—whether through infection or vaccination—your body produces these antibodies to help protect you from getting sick again. This test detects these antibodies in your serum to determine if your immune system has mounted a response.
Why Might You Need This Test?
Doctors may order this test to check if you’ve developed immunity to COVID-19 after recovery from infection or vaccination. It can also help monitor immune response in people who have had COVID-19 or are at higher risk of severe illness.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The blood is then sent to a lab where it is analyzed using an immunoassay method to detect IgG antibodies specific to SARS-CoV-2.
What Are Possible Results?
Results can be positive (indicating the presence of IgG antibodies), negative (no detectable antibodies), or inconclusive (depending on lab interpretation). A positive result suggests your body has recognized the virus and produced antibodies, but it does not confirm active infection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A positive IgG test indicates past exposure to the virus, meaning you likely had COVID-19 or received a COVID-19 vaccine. However, IgG alone does not prove you are currently infected. It’s important to note that antibody levels can vary over time, and a negative test does not always mean you are not immune. This test is often used alongside other clinical assessments to guide decisions about vaccination, travel, or exposure risk.
Short name
IgG Antibody to COVID-19 Virus
Frequently asked questions
What Does a Positive Result Mean?
Does This Test Replace a COVID-19 Test for Active Infection?
How Long Do IgG Antibodies Stay in My System?
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