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

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

This test measures the presence of IgG antibodies in your blood that your immune system produces in response to exposure to the virus that causes COVID-19.

Quick summary

["IgG antibodies indicate a past infection or immunity from COVID-19."]

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

Key facts at a glance

LOINC
105910-4
Short code
SARS-CoV-2 IgG Spec-aCnc
Synonyms
SARS-CoV-2 IgG Spec-aCnc
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?

IgG antibodies are a type of antibody your immune system makes after you’ve been exposed to the virus. They can stay in your body for months or even years, providing long-term protection. This test detects these antibodies in your serum or plasma to help determine if you’ve had prior exposure to SARS-CoV-2.

Why Might You Need This Test?

Doctors may order this test to confirm past infection, assess immunity, or evaluate exposure in high-risk settings (e.g., healthcare workers, travelers). It’s also used in screening for immunity before certain procedures or vaccinations.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is then processed to separate serum or plasma for antibody detection using an immunoassay method, which identifies IgG antibodies against the virus’s spike protein.

What Are the Results Typically Used For?

Results help determine if you’ve developed immunity from a prior COVID-19 infection, which may influence decisions about vaccination, travel, or workplace safety. They’re not a substitute for current infection status (e.g., PCR or antigen tests).

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Understanding IgG Antibodies

Short name

IgG Antibody to SARS-CoV-2

Frequently asked questions

What does a positive result mean?
A positive IgG result suggests you’ve likely had COVID-19 in the past and may have some level of immunity. However, this does not guarantee protection against future infection, as immunity can vary.
How long do IgG antibodies last?
IgG antibodies can remain in your system for months to years after infection, but their effectiveness and levels may decline over time. This is why some people may need booster doses or additional testing.
Can this test detect current COVID-19 infection?
No, this test only detects past exposure through IgG antibodies. For active infection, you’d need a PCR or antigen test.
  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