Serum Anti-SARS-CoV-2 Immunoglobulin G (IgG) Antibody Test
This test measures the presence of Immunoglobulin G (IgG) antibodies in your blood against the virus that causes COVID-19. IgG antibodies are part of your immune system’s long-term defense.
["IgG antibodies help your body remember the virus for future protection."]
Key facts at a glance
- LOINC
- 97112-7
- Short code
- WORKEDDURINGTHECOVID19OUTBREAK
- Synonyms
- —
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 3.5
- Ref high
- 5
- Critical range
- 2.5 N/A – 6.5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84132
- SNOMED
- 110742001
- 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 in response to an infection. After recovering from COVID-19, your body may continue producing IgG antibodies for months or even years. These antibodies help your immune system recognize and fight off the virus if you become infected again. This test checks for these antibodies in your serum, which is the liquid part of your blood after blood cells and clots are removed.
Why Might You Need This Test?
Healthcare providers may order this test to determine if you have developed immunity to COVID-19 after recovery. It can also be used to monitor immune response in certain clinical settings, such as during or after vaccination or in research studies related to COVID-19.
How Is the Sample Collected?
A small amount of blood is drawn from a vein in your arm by a healthcare professional. This process is quick and typically causes only minor discomfort. The blood sample is then sent to a lab for testing.
What Are the Possible Results?
Results can be positive (indicating the presence of IgG antibodies), negative (no detectable antibodies), or inconclusive (if the test cannot determine antibody presence). Positive results suggest your immune system has recognized the virus, but they do not guarantee full immunity or protection against future infection.
Reference range
Adult: 3.5-5.0 mmol/LN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
IgG antibody testing is primarily used to assess past infection or immune response to COVID-19. Positive results indicate that your body has likely been exposed to the virus and developed antibodies, which may offer some protection. However, IgG alone does not confirm immunity or protect against reinfection. Other factors, such as vaccination status and ongoing immune response, also play a role in overall protection.
Short name
IgG Antibody to COVID-19
Frequently asked questions
How Long Do IgG Antibodies Last?
Does a Positive IgG Test Mean I’m Safe from COVID-19?
Can IgG Antibody Levels Be Used to Track My Immune Response?
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