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SARS-CoV-2 Antibody (Serum) – Total IgG/IgM

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

This test detects antibodies in your blood that your immune system produces in response to the SARS-CoV-2 virus, which causes COVID-19. Antibodies can help identify past infection or immunity.

Quick summary

["This test helps determine if you’ve had COVID-19 or if your body has developed immunity through vaccination or prior infection."]

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

Key facts at a glance

LOINC
33971-3
Short code
SARS-CoV Urb Ab Titr Ser IF
Synonyms
SARS-CoV Urb Ab Titr Ser IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 total immunoglobulin (IgG and IgM) antibodies against the SARS-CoV-2 virus. IgM antibodies typically appear early in infection and decline over time, while IgG antibodies develop later and can persist longer, indicating long-term immunity or past exposure.

Why Might Your Doctor Order This Test?

Your doctor may recommend this test to check for past COVID-19 infection, assess immunity status after vaccination, evaluate exposure in high-risk settings, or monitor immune response in certain medical conditions.

How Is the Sample Collected?

A blood sample is drawn from a vein in your arm by a healthcare professional. The blood is then processed to separate serum for testing.

What Are the Possible Results?

Results may show positive (indicating antibodies were detected), negative (no detectable antibodies), or inconclusive (insufficient sample or unclear results). Follow-up testing may be needed if results are unclear.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Positive results suggest past infection or immunity, but they do not guarantee protection against future infection. IgG antibodies alone may not fully indicate immunity. This test is often used alongside clinical judgment, symptoms, and other diagnostic criteria.

Short name

SARS-CoV-2 Antibody Test

Frequently asked questions

What Does a Positive Result Mean?
A positive result means your body has produced antibodies against SARS-CoV-2, which could indicate you had COVID-19 at some point or were vaccinated. However, antibodies alone do not confirm current immunity or protect against future infection.
Can This Test Be Used to Confirm a Recent Infection?
No, this test primarily detects past infection or immunity. For recent infection confirmation, PCR or antigen tests are typically used, as they detect the virus itself rather than antibodies.
How Long Do Antibodies Last After Infection?
IgG antibodies may persist for months to years after infection, but their levels can decline over time. IgM antibodies usually fade within weeks. Vaccination can boost antibody levels, but immunity may require ongoing monitoring.
  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