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Immunoglobulin G (IgG) Subclass 4 Blood Mass Concentration

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

This test measures the amount of Immunoglobulin G (IgG) subclass 4 in your blood, a type of antibody that plays a role in immune response.

Quick summary

["IgG4 antibodies may be elevated in certain autoimmune conditions or inflammatory diseases."]

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

Key facts at a glance

LOINC
106806-3
Short code
IgG4 BldCo Neph-mCnc
Synonyms
IgG4 BldCo Neph-mCnc
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nephelometry
CPT
82784
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms or conditions linked to IgG4-related diseases, such as autoimmune pancreatitis, IgG4-related sclerosing cholangitis, or other inflammatory conditions. It can also help monitor treatment responses in patients already diagnosed with these conditions.

What to Expect Before the Test

No special preparation is typically needed. You may have a small needle inserted into a vein in your arm to draw blood. If you experience discomfort, let your healthcare provider know.

What the Test Results Mean

IgG4 levels can vary widely among individuals. Elevated levels may suggest an underlying autoimmune or inflammatory condition, while normal or low levels do not definitively rule out these conditions. Results should be interpreted by your healthcare provider in the context of your medical history and symptoms.

Common Conditions Monitored or Diagnosed

IgG4-related diseases, such as IgG4-related sclerosing cholangitis, autoimmune pancreatitis, and certain lymphoproliferative disorders, may show elevated IgG4 levels. This test can help diagnose or monitor these conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG4 Blood Level

Frequently asked questions

What does an abnormal IgG4 level indicate?
An elevated IgG4 level may indicate an active IgG4-related disease or an inflammatory process. However, IgG4 can also be elevated in other conditions, such as certain infections or chronic inflammatory diseases. Your healthcare provider will consider other factors, including symptoms, medical history, and additional tests, to determine the cause.
How often should I get this test?
The frequency of testing depends on your medical condition and treatment plan. If you are being monitored for an IgG4-related disease, your healthcare provider may recommend periodic testing to track changes in your IgG4 levels and assess the effectiveness of your treatment.
Can diet or lifestyle affect IgG4 levels?
Diet and lifestyle factors generally do not significantly affect IgG4 levels. However, if you suspect a specific dietary component may influence your immune response, discuss it with your healthcare provider. Focus on managing underlying medical conditions and following prescribed treatments for optimal results.
  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