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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 Immunoglobulin G (IgG) antibodies against the SARS-CoV-2 virus, which indicates a past infection with COVID-19. IgG antibodies are typically developed several weeks after initial infection and can remain in your system for a longer period.

Quick summary

["IgG antibodies help your immune system remember the virus for potential future protection."]

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

Key facts at a glance

LOINC
94547-7
Short code
SARS-CoV-2 IgG+IgM SerPl Ql IA
Synonyms
SARS-CoV-2 IgG+IgM 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

What Does This Test Measure?

IgG antibodies are a type of antibody produced by your immune system in response to an infection. In this test, we detect IgG that specifically targets the SARS-CoV-2 virus, which causes COVID-19. These antibodies are part of your body’s long-term immune response and can help identify if you have had COVID-19 previously.

Why Might You Need This Test?

Doctors may order this test to confirm past infection with COVID-19, especially if you have symptoms that suggest recovery from the virus or if you have been exposed to someone with COVID-19. It can also be used in research or to assess immune response in vaccinated individuals.

How Is the Sample Collected?

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate the serum or plasma, which is tested for IgG antibodies. This process is quick and typically done in a clinical setting.

What Does a Positive Result Mean?

A positive result means your body has produced IgG antibodies against SARS-CoV-2, suggesting you likely had COVID-19 at some point. However, it does not confirm active infection; it only indicates prior exposure and immune response.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: IgG Antibodies and COVID-19

Short name

IgG Antibody to SARS-CoV-2

Frequently asked questions

What are the normal reference ranges for this test?
There are no standard numeric reference ranges provided for IgG antibody tests because they vary based on the test method and sensitivity. A positive result means detectable antibodies are present, while a negative result suggests no detectable IgG antibodies at the time of testing.
Can IgG antibodies protect me from getting COVID-19 again?
IgG antibodies provide some protection against reinfection, but they do not guarantee immunity. The level of protection can vary, and other factors like vaccination status and immune response play a role. Current science suggests that immunity from infection alone may not be as strong as that provided by vaccination.
How long do IgG antibodies last after COVID-19?
IgG antibodies can remain in your system for months to years after infection, but their levels may gradually decrease over time. Some people may still have detectable IgG antibodies for an extended period, while others may lose them. This can vary widely among individuals.
  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