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Serum IgG Immunoglobulin (Total)

Published: August 9, 2026Updated: August 17, 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 and diseases.

Quick summary

["IgG supports long-term immunity and helps fight infections."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
82982-0
Short code
Exocrine pancreas IgA+IgG SerPl Ql IF
Synonyms
Exocrine pancreas IgA+IgG SerPl Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Critical range
0.5 N/A – —
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 Is Immunoglobulin G (IgG)?

IgG is the primary antibody in your bloodstream. It plays a crucial role in defending your body against bacteria, viruses, and toxins. Produced by your immune system, IgG helps neutralize foreign invaders and marks them for destruction by other immune cells. Levels of IgG can vary depending on your health, immune response, and exposure to infections.

Why Might You Need This Test?

Doctors may order an IgG test to check for immune system issues, such as low immunity (hypogammaglobulinemia), infections, autoimmune diseases, or to monitor treatment responses in conditions like HIV, cancer, or chronic illnesses. It can also help diagnose or manage conditions like cystic fibrosis, HIV, or certain allergies.

What Does a Low or High IgG Level Mean?

Low IgG levels may indicate a weakened immune system, making you more susceptible to infections. High IgG levels can sometimes suggest chronic infections, autoimmune diseases, or allergic reactions, though they’re less common.

When Might You Get Results Back?

Results are typically ready within 1–3 business days, depending on your lab’s processing time. Your doctor will discuss the results with you and explain any changes needed in your care.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Level

Frequently asked questions

Could I have symptoms before my test results come back?
You may experience symptoms like frequent infections, fatigue, or unexplained illnesses even before IgG levels drop significantly. If you’ve been diagnosed with a condition affecting immunity, your doctor may recommend monitoring IgG levels regularly.
What if my IgG level is outside the normal range?
If your IgG level is low, your doctor may recommend additional tests or treatments to boost your immune system, such as immunoglobulin therapy. If high, further evaluation might be needed to determine the underlying cause, like chronic infections or autoimmune activity.
Does diet affect IgG levels?
Diet can influence overall immune health, but it doesn’t directly affect IgG levels. Eating a balanced diet rich in vitamins (like vitamin D and zinc) and staying hydrated supports immune function, though IgG is primarily measured in blood tests.
  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 17, 2026. · Read our editorial policy