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SARS-CoV-2 Immunoglobulin G (IgG) Antibody, Serum/Plasma

Published: August 9, 2026Updated: August 16, 2026

This test detects antibodies (specifically IgG) produced by your immune system in response to exposure to the SARS-CoV-2 virus, which causes COVID-19. IgG antibodies are part of your body’s long-term immune response.

Quick summary

["This test helps determine if you’ve had prior infection with COVID-19 or received a vaccine that triggers an immune response."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
94563-4
Short code
SARS-CoV-2 IgG SerPl Ql IA
Synonyms
SARS-CoV-2 IgG SerPl Ql IA
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
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

Your healthcare provider may order this test to check for past infection with SARS-CoV-2, even if you’ve never had symptoms. It can also be used to monitor immunity after vaccination or recovery from COVID-19. Some people may also get this test to assess immune response to treatment for chronic conditions that affect the immune system.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from a vein in your arm. The sample is collected in a tube and sent to the lab for testing. The process takes about 15 minutes.

What the Test Results Mean

Positive results indicate the presence of IgG antibodies, suggesting you’ve likely had prior exposure to the virus (either through infection or vaccination). However, IgG alone doesn’t confirm active infection. Negative results mean no detectable IgG antibodies were found, which could mean you’ve never been exposed or the test was taken too early after exposure.

Possible Limitations

IgG antibodies may take weeks to develop after infection or vaccination. If you’re tested too soon, you may not have enough antibodies to detect. Additionally, some medications or immune conditions can affect antibody levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Antibody to SARS-CoV-2

Frequently asked questions

How long do IgG antibodies last?
IgG antibodies can persist for months or even years after infection or vaccination, but their levels may gradually decline over time. They provide long-term immunity but don’t guarantee lifelong protection. Some people may need booster doses or monitoring for immunity.
Can this test detect COVID-19 if I’m currently sick?
No, this test only detects IgG antibodies, which develop after exposure. If you’re currently experiencing COVID-19 symptoms, you should not rely on this test for diagnosis. Instead, use rapid antigen tests or PCR tests for active infection.
Does this test differentiate between infection and vaccination?
No, this test can’t distinguish between antibodies produced from natural infection or vaccination. However, it confirms prior exposure to the virus, regardless of how that exposure occurred.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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