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SARS-CoV-2 Immunoglobulin G (IgG) Antibody, 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 help your body fight off past infections and provide long-term immunity."]

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

Key facts at a glance

LOINC
94505-5
Short code
SARS-CoV-2 IgG SerPl IA-aCnc
Synonyms
SARS-CoV-2 IgG SerPl IA-aCnc
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 your immune system makes after you’ve been exposed to the SARS-CoV-2 virus. These antibodies can stay in your blood for months or even years after infection, helping your body remember how to fight the virus if you’re exposed again. This test detects these antibodies to determine if you’ve had a past infection with COVID-19.

Why Might You Need This Test?

Doctors may order this test to confirm past COVID-19 infection, especially if you’ve had symptoms or exposure but test negative for current infection. It can also help assess immune response in people recovering from COVID-19 or those with weakened immune systems.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is then sent to a lab for analysis using an immunoassay method to detect IgG antibodies.

What Are the Possible Results?

Results are typically reported as positive or negative. A positive result indicates the presence of IgG antibodies, suggesting past exposure to the virus. A negative result means no detectable IgG antibodies were found in this sample.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Antibody to SARS-CoV-2

Frequently asked questions

How long do IgG antibodies last after COVID-19?
IgG antibodies can persist for months to years after infection, though their levels may gradually decline over time. This test does not measure antibody levels but rather presence or absence, so results can change if retested later.
Can this test tell me if I’m currently infected with COVID-19?
No, this test specifically looks for IgG antibodies, which indicate past infection, not current infection. For active infection, tests like PCR or antigen tests are used instead.
What does a positive IgG result mean?
A positive IgG result means your immune system has likely encountered the SARS-CoV-2 virus before and produced antibodies to remember it. This does not guarantee immunity against future infections, but it suggests your body has some level of protection.
  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