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Total IgG Immunoglobulin (Serum)

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

This test measures the amount of Immunoglobulin G (IgG), the most common type of antibody in your blood. IgG helps protect your body from infections by fighting bacteria and viruses.

Quick summary

["IgG antibodies are vital for long-term immunity and are often checked if you have frequent infections or immune-related conditions."]

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

Key facts at a glance

LOINC
35880-4
Short code
tTG IgM Ser-aCnc
Synonyms
tTG IgM Ser-aCnc
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

Why Might This Test Be Done?

Your doctor may order this test to evaluate your immune system. Common reasons include diagnosing or monitoring conditions like immunodeficiency, autoimmune diseases, or infections. It may also be used before vaccines to check baseline antibody levels or after treatment to assess response.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein in your arm, and a blood sample will be collected. This usually takes just a few minutes and is generally painless.

What the Results Mean

IgG levels can vary based on age, overall health, and medical conditions. Low levels might suggest a weakened immune system, while very high levels could indicate chronic infections, certain cancers, or autoimmune disorders. Your doctor will interpret the results in the context of your health history.

Common Conditions Monitored

This test is often used to monitor conditions such as HIV/AIDS, certain cancers (e.g., lymphoma), chronic infections (e.g., hepatitis), and congenital immunodeficiencies. It can also help track immune response after vaccination or treatment with immune-modulating therapies.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

What causes IgG levels to be low?
Low IgG levels can be caused by primary immune deficiencies (like Common Variable Immunodeficiency), chronic illnesses (such as HIV/AIDS or cirrhosis), or certain medications that suppress the immune system. It may also appear in newborns due to maternal antibodies waning.
What causes IgG levels to be high?
High IgG levels may result from chronic infections (e.g., hepatitis, tuberculosis), autoimmune diseases (e.g., rheumatoid arthritis), or certain cancers (e.g., multiple myeloma). Long-term use of certain medications or exposure to toxins can also lead to elevated IgG.
How often should I get this test?
Your doctor will determine the frequency based on your health needs. For example, people with immunodeficiency may need regular monitoring, while others might only need it if symptoms or treatment changes occur.
  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