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Anti-SARS-CoV-2 IgG (Serum) - Immunoassay

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

This test measures the presence of antibodies called IgG in your blood that your immune system produces in response to exposure to the SARS-CoV-2 virus, which causes COVID-19.

Quick summary

["IgG antibodies indicate past infection and long-term immune response to COVID-19."]

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

Key facts at a glance

LOINC
27230-2
Short code
Deprecated S pneum19 IgG Ser IA-mCnc
Synonyms
Deprecated S pneum19 IgG Ser IA-mCnc
Category
coagulation
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 immune protein your body makes after recovering from COVID-19 or in response to vaccination. These antibodies help your immune system remember the virus and fight it more effectively if you become infected again. This test detects IgG specifically, which typically develop several weeks after initial infection or vaccination.

Why Might You Need This Test?

Healthcare providers may order this test to confirm past COVID-19 infection, assess immune response to vaccination, or evaluate long-term immunity in certain situations. It can also help determine if you’ve developed immunity after recovering from COVID-19.

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The sample is then tested using an immunoassay method to detect IgG antibodies against the SARS-CoV-2 virus.

What Are Possible Results?

A positive result means your body has produced IgG antibodies, suggesting you’ve likely had COVID-19 or been vaccinated. A negative result means no detectable IgG antibodies were found, but this does not rule out past infection if testing was done too early.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Anti-SARS-CoV-2 IgG

Frequently asked questions

When Might I Get a False Result?
IgG tests can sometimes yield false negatives if taken too soon after infection (within 2–3 weeks) or too soon after vaccination. False positives are rare but can occur with certain medical conditions or cross-reactions. Your healthcare provider will discuss timing and interpretation with you.
What Does It Mean If My IgG Test Is Negative?
A negative IgG result means no detectable antibodies were found at the time of testing. However, this does not confirm you’ve never been infected. If you suspect past exposure, discuss retesting or other diagnostic options with your doctor, especially if symptoms persist.
How Often Should I Get This Test?
There is no routine recommendation for IgG testing unless you have specific medical reasons (e.g., evaluating immunity for travel, workplace, or other high-risk settings). Your healthcare provider will determine if retesting is needed based on your situation and medical history.
  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