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Total Immunoglobulin G (IgG) Level

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

This test measures the amount of Immunoglobulin G (IgG), a type of antibody in your blood that helps fight infections and supports immune function.

Quick summary

["IgG helps protect your body against diseases and supports immune health."]

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

Key facts at a glance

LOINC
51784-7
Short code
Lot # Rh Imm Gl
Synonyms
Lot # Rh Imm Gl
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 Is Done

Doctors may order an IgG test to check for immune system issues, such as low antibody levels that could indicate conditions like HIV, severe infections, or certain autoimmune diseases. It may also be used to monitor treatment responses in patients with immune-related disorders.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm, and a small amount of blood will be drawn. The process usually takes a few minutes.

What the Test Results Mean

Results may be reported as a range or a single value, but exact reference ranges can vary by lab. Low IgG levels may suggest weakened immunity, while very high levels might indicate certain immune disorders or chronic infections. Your healthcare provider will interpret results in the context of your overall health.

Common Conditions Monitored

IgG levels are often checked in patients with suspected immune deficiencies, chronic infections, or autoimmune diseases. It can also be used to evaluate immune responses in newborns or individuals receiving immune-modifying treatments.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Level

Frequently asked questions

What Does It Feel Like to Have This Test Done?
Most people experience only mild discomfort from the needle stick, which may include a slight pinch or stinging sensation. Some may feel a small bruise or swelling at the site, but these are usually temporary.
How Often Should I Get This Test?
The frequency depends on your medical condition and treatment plan. Your doctor will determine how often you need this test based on your individual needs, such as monitoring immune function or response to treatment.
Can I Eat or Drink Before This Test?
You can eat and drink normally before this test unless your doctor advises otherwise. No fasting is required for this blood test.
  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