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Serum 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. IgG helps fight infections and is important for long-term immunity.

Quick summary

["IgG helps protect your body from infections and supports long-term immunity."]

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

Key facts at a glance

LOINC
95713-4
Short code
WEEV IgA Spec Ql IA
Synonyms
WEEV IgA Spec Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 This Test Measure?

IgG is the most common type of antibody in your blood. It plays a key role in defending against bacteria and viruses. Your body produces IgG in response to infections or vaccines to help you stay healthy over time.

Why Might You Need This Test?

Doctors may order an IgG test to check for immune system issues, such as low levels of antibodies that could affect your ability to fight infections. It can also help diagnose conditions like certain autoimmune diseases or immune deficiencies.

When Might You Get This Test?

You might have this test if you have frequent infections, unexplained fatigue, or symptoms like frequent colds, pneumonia, or recurring skin infections. It may also be part of a routine check-up for people with known immune system problems.

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 to draw a blood sample. The process usually takes a few minutes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

How long does it take to get the results of this test?
Results from this test are typically available within a few days to a week, depending on your lab and healthcare provider. Follow-up with your doctor to discuss the results and any next steps.
What are the normal ranges for IgG levels?
IgG levels vary among individuals, and specific reference ranges are not provided here. Your doctor will interpret the results in relation to your overall health and medical history.
Can low or high IgG levels cause health problems?
Low IgG levels can weaken your immune system, making you more susceptible to infections. High IgG levels might be seen in chronic infections, certain autoimmune diseases, or as a reaction to vaccines. Always discuss any concerns with your healthcare provider.
  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