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Total IgG Antibody Level (Serum)

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

This test measures the amount of Immunoglobulin G (IgG) antibodies in your blood. IgG is the most common type of antibody and plays a key role in long-term immunity.

Quick summary

["IgG antibodies help protect your body from infections and diseases over time."]

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

Key facts at a glance

LOINC
55727-2
Short code
tTG IgA+IgG Pnl Ser
Synonyms
tTG IgA+IgG Pnl Ser
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 IgG Antibody Testing Measure?

IgG antibodies are produced by your immune system in response to infections, vaccines, or other immune challenges. This test helps assess your immune response, monitor chronic conditions, or evaluate exposure to certain pathogens.

When Might You Need This Test?

Your healthcare provider may order this test if you have symptoms of an immune disorder, if you’ve been exposed to a specific illness, or if you’re being monitored for conditions like chronic infections, autoimmune diseases, or after receiving vaccines.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The blood is then processed to separate serum (the liquid part without clots) for testing. The IgG level is measured using an immunoassay method, which detects the presence and concentration of antibodies.

What Are Possible Results?

Results may be compared to a reference range specific to your age, health status, or clinical situation. Abnormal results could indicate either insufficient antibody production (e.g., in immune deficiencies) or excessive levels (e.g., in chronic infections or autoimmune diseases).

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

IgG antibody levels are critical for diagnosing or managing conditions such as HIV, hepatitis, certain autoimmune diseases, or immune system disorders. They also help determine vaccine effectiveness or guide treatment plans for chronic infections. Low IgG levels may signal a weakened immune response, while high levels could point to overactive immune activity or chronic exposure to pathogens.

Short name

IgG Antibody Test

Frequently asked questions

Why might my IgG antibody test be ordered even if I feel healthy?
Your provider may order this test to check for underlying immune function, monitor long-term immunity after vaccination, or investigate unexplained symptoms like frequent infections, fatigue, or unexplained illnesses. It’s also used in research or clinical trials to assess immune responses.
What does it mean if my IgG levels are higher than expected?
Higher-than-normal IgG levels can occur with chronic infections (e.g., hepatitis, HIV), autoimmune diseases (e.g., lupus), or certain medications that boost antibody production. Your provider will consider your medical history and other test results to interpret these findings.
Can IgG antibody tests be affected by recent vaccinations or infections?
Yes, vaccinations or recent infections can temporarily alter IgG levels. If you’ve received a vaccine or had an illness recently, your provider may wait for results to stabilize before drawing conclusions or may adjust the interpretation accordingly.
  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