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SARS-CoV-2 IgG Antibody (Serum/Plasma) - Confirmatory

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

This test detects antibodies (IgG) produced by your immune system in response to exposure to the SARS-CoV-2 virus, which causes COVID-19. IgG antibodies typically develop several weeks after infection or vaccination.

Quick summary

["This test helps confirm past infection or immunity from COVID-19."]

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

Key facts at a glance

LOINC
42957-1
Short code
SARS-CoV IgG Ser Ql
Synonyms
SARS-CoV IgG Ser Ql
Category
chemistry
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?

The test measures the presence of IgG antibodies against specific proteins from the SARS-CoV-2 virus. These antibodies are part of your immune response and can indicate whether your body has encountered the virus before, either through infection or vaccination.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms of COVID-19, have been exposed to someone with COVID-19, or if you are recovering from an infection. It can also be used to assess immunity after vaccination or to monitor long-term immunity.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood sample drawn from a vein in your arm, similar to other blood tests. If you are using blood thinners, inform your healthcare provider beforehand.

What to Expect During the Test

The blood sample will be collected in a tube and sent to a laboratory for analysis. The test involves an immunoassay method to detect IgG antibodies. Results are usually available within a few days.

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 after COVID-19 infection or vaccination?
IgG antibodies can persist for months or even years after infection or vaccination, but their exact duration varies among individuals. Some people may have detectable levels for a longer period, while others may experience a decline over time. Follow-up testing may be recommended if needed for ongoing immunity assessment.
Can IgG antibodies protect me from getting COVID-19 again?
IgG antibodies provide some protection against reinfection, but they are not a guarantee. The level of protection can vary, and other factors like vaccination status, age, and overall health also play a role. Current guidance often recommends staying up to date with COVID-19 vaccines for optimal protection.
What if my IgG test result is positive but I haven’t had symptoms of COVID-19?
A positive IgG result can occur after exposure to the virus without symptoms (asymptomatic infection) or after vaccination. It does not necessarily mean you were infected recently. If you suspect recent exposure or symptoms, additional testing for other markers (like IgM or viral testing) may be needed to clarify your infection status.
  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