Skip to content

Total Immunoglobulin G (IgG) Concentration

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

This test measures the amount of Immunoglobulin G (IgG), a type of antibody in your blood. IgG helps protect your body from infections and plays a key role in long-term immunity.

Quick summary

["IgG helps fight infections and supports immune function; low or high levels may indicate immune system issues."]

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

Key facts at a glance

LOINC
61230-9
Short code
Roach IgE/IgE total %
Synonyms
Roach IgE/IgE total %
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 This Test Might Be Ordered

Your healthcare provider may order this test to check for immune system problems, such as low IgG levels that could make you more susceptible to infections. It might also be done if you have symptoms like frequent illnesses, slow wound healing, or unexplained fatigue. In some cases, it’s part of evaluating conditions like immunodeficiency disorders or monitoring treatment for immune-related diseases.

What to Expect Before the Test

No special preparation is usually needed. You may have a small needle inserted into a vein in your arm or hand to draw blood. If you’re nervous, let your healthcare provider know so they can help make it more comfortable.

What the Test Results Mean

IgG levels vary depending on age, overall health, and other factors. While reference ranges can differ by lab, very low levels might suggest weakened immunity, while very high levels could indicate chronic infections, autoimmune disorders, or certain diseases. Your results will be discussed with your provider to understand their specific meaning for you.

Common Conditions Affecting IgG Levels

Low IgG levels may be linked to primary immunodeficiency diseases, certain autoimmune conditions, or conditions that affect nutrient absorption (like celiac disease). High IgG levels can be seen in chronic infections, inflammatory diseases, or as a reaction to certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Level

Frequently asked questions

What causes IgG levels to be different than usual?
IgG levels can change due to infections (like colds or flu), chronic illnesses (such as lupus or rheumatoid arthritis), certain medications, or even genetics. If your IgG level is outside the expected range, your healthcare provider will review your medical history and other test results to determine the cause.
Can IgG levels change over time?
Yes, IgG levels can fluctuate. They may rise during infections or illnesses and drop after recovery. Some people naturally have higher or lower baseline levels due to their immune system or overall health. Regular monitoring might be needed if you have a condition that affects immunity.
Is there anything I can do to support my IgG levels?
While you can’t directly change your IgG levels, maintaining a healthy immune system through good nutrition, staying hydrated, managing stress, and getting enough sleep can support overall immune function. If you suspect an issue with your IgG, talk to your provider about ways to address it, such as dietary changes or supplements if recommended.
  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