Anti-SARS-CoV-2 IgG Antibody (Serum)
This test measures the presence of Immunoglobulin G (IgG) antibodies against SARS-CoV-2, the virus responsible for COVID-19. IgG antibodies are part of your immune system’s long-term response and can indicate past infection or immunity.
["IgG antibodies may help determine if you’ve had COVID-19 and whether your body retains immunity."]
Key facts at a glance
- LOINC
- 25284-1
- Short code
- Deprecated S pneum19 IgG 2:1 Ser-Rto
- Synonyms
- Deprecated S pneum19 IgG 2:1 Ser-Rto
- 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
Why This Test Is Done
Doctors may order this test to assess whether you’ve developed immunity to COVID-19 after recovering from the virus or after vaccination. It can also help evaluate immune response in certain clinical settings, such as evaluating vaccine effectiveness or monitoring immune status in high-risk individuals.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample from a vein in your arm. The process is quick and typically done in a doctor’s office or lab. If you’re nervous, let your healthcare provider know so they can prepare you appropriately.
What the Results Mean
Positive results suggest you have developed IgG antibodies, which may mean you’ve had COVID-19 or received a vaccine that triggered an immune response. However, having IgG antibodies does not guarantee full immunity or protection against reinfection. Negative results mean you likely do not have detectable IgG antibodies at this time.
Possible Limitations
IgG antibody tests can’t confirm a current infection. They also may not detect antibodies if your immune system hasn’t responded strongly or if the test was taken too soon after exposure. False negatives can occur, especially in early infection or if the test was done too soon after exposure.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
IgG antibody testing is primarily used to assess past infection or vaccine-induced immunity rather than diagnose active COVID-19. It can guide decisions about travel, workplace safety, or participation in clinical trials. However, it should not replace other diagnostic tests like PCR or antigen tests for current infection.
Short name
IgG Antibody to COVID-19
Frequently asked questions
When might I need this test?
What does a positive result mean?
Can this test detect antibodies if I’ve had COVID-19 recently?
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