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Immunoassay for IgG Subclass 1 (IgG1) Antibody in Serum

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

This test measures the amount of Immunoglobulin G (IgG) subclass 1 antibodies in your blood. IgG antibodies are part of your immune system and help fight infections.

Quick summary

["IgG1 antibodies play a key role in defending against bacteria and viruses."]

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

Key facts at a glance

LOINC
42601-5
Short code
IC IgG Snv C1Q Bind-aCnc
Synonyms
IC IgG Snv C1Q Bind-aCnc
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
c-q-binding-assay
CPT
82784
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Does This Test Measure?

IgG1 antibodies are a specific type of antibody (also called immunoglobulin) produced by your immune system. They are one of four subclasses of IgG antibodies, each with slightly different functions. This test specifically looks at IgG1 levels, which can vary depending on your immune response, health status, or certain medical conditions.

Why Might You Need This Test?

Doctors may order this test to evaluate immune function, diagnose or monitor autoimmune diseases, assess immune responses to vaccines or infections, or investigate symptoms like recurrent infections, fatigue, or unexplained swelling.

How Is the Sample Collected?

A small amount of blood is drawn from a vein, usually in your arm, using a needle. The blood sample is then sent to a lab for testing.

What Are Possible Results?

Results are typically reported as a concentration of IgG1 antibodies in the blood, though exact reference ranges can vary by lab. Higher or lower than expected levels may indicate different health conditions or immune responses.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG1 Antibody Level

Frequently asked questions

How often will I need this test?
This test is usually performed once or occasionally as part of a broader evaluation. Your doctor will determine how often you need it based on your medical history, symptoms, and treatment plan.
What do abnormal IgG1 levels mean?
Abnormally low IgG1 levels may suggest immune deficiencies, chronic illnesses, or conditions affecting antibody production. Abnormally high levels could be linked to autoimmune diseases, certain infections, or overactive immune responses. Always discuss results with your healthcare provider.
Can lifestyle changes affect IgG1 levels?
While diet, exercise, and stress management can support overall immune health, IgG1 levels are primarily influenced by immune system activity and medical conditions. Your doctor will guide you on how lifestyle factors may interact with your test 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