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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 protect your body from infections and is important for long-term immunity.

Quick summary

["IgG levels help identify immune system function and potential deficiencies or excesses."]

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

Key facts at a glance

LOINC
69030-5
Short code
Enterocyte IgG Ser Ql
Synonyms
Enterocyte IgG Ser Ql
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 This Test Is Done

Your healthcare provider may order this test to check for immune system health, diagnose conditions like immunodeficiency, or monitor treatment responses in diseases such as HIV, lupus, or certain cancers. It may also be done if you have frequent infections, unexplained fatigue, or symptoms like frequent colds or infections in the sinuses, lungs, or urinary tract.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for a few hours before the test if it involves drawing blood from your arm. Wear a loose shirt or sleeve to make drawing blood easier.

What Happens During the Test

A healthcare professional will clean your arm with an antiseptic and insert a small needle into a vein. Blood will be collected into a tube. The process usually takes a few minutes. You may feel a brief pinch or sting, but it should not cause significant discomfort.

What Happens After the Test

After the blood is drawn, the needle will be removed, and pressure will be applied to the site to stop any bleeding. You can resume normal activities immediately. If you experience any unusual symptoms like excessive bruising or swelling, contact your healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

What does an abnormal IgG level mean?
An abnormal IgG level could suggest an underlying immune issue. Low levels might mean your immune system isn’t producing enough antibodies to fight infections, while high levels could indicate chronic illness or overactive immune responses. Your healthcare provider will discuss these results with you and may recommend further tests or treatments.
Can diet affect IgG levels?
Diet can influence overall immune health, but it does not directly affect IgG levels. A balanced diet rich in vitamins, minerals, and proteins supports immune function, but IgG levels are primarily determined by your body’s immune response and health conditions.
Is IgG testing painful?
The blood draw itself is usually not painful but may cause a brief pinch or discomfort. Most people describe it as mild and over quickly. If you have a hard time with needles, let your healthcare provider know so they can take extra precautions.
  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