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IgG Subclass 2 (Immunoglobulin G2) Antibody Level

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of Immunoglobulin G2 (IgG2) antibodies in your blood. IgG2 is one type of antibody that helps fight certain infections, including some bacteria and viruses.

Quick summary

["IgG2 antibodies play a key role in protecting your body against specific infections, and levels can be checked if you have certain immune-related conditions or symptoms."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
102781-2
Short code
Oyster IgG RAST
Synonyms
Oyster IgG RAST
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rast
CPT
84484
SNOMED
302774002
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?

IgG2 antibodies are a part of your immune system’s defense. They are particularly important for fighting infections caused by bacteria, such as some types of pneumonia or respiratory infections. This test specifically looks at the concentration of IgG2 antibodies in your blood, which can help doctors understand how well your immune system is responding to certain pathogens.

Why Might You Need This Test?

Your doctor may recommend this test if you have symptoms like frequent infections, particularly those caused by bacteria, or if you have a condition that affects your immune system, such as certain autoimmune diseases. It can also be used to monitor treatment responses in people with immune-related disorders.

How Is the Test Performed?

A small blood sample is taken from a vein, usually in your arm. The sample is then sent to a lab for analysis using an immunoassay method, which detects the presence and amount of IgG2 antibodies in your blood.

What Do the Results Mean?

Results can vary widely depending on your health, age, and other factors. Lower than expected levels of IgG2 antibodies might suggest a weakened immune response to certain infections, while higher levels may indicate an overactive immune reaction or exposure to specific antigens. Your doctor will interpret the results in the context of your overall health and medical history.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG2 Antibody Test

Frequently asked questions

What Are Common Causes of Abnormal IgG2 Levels?
Abnormal IgG2 levels can result from various factors, including genetic predispositions, certain autoimmune diseases, or immune system disorders like CVID. Frequent or severe infections, especially bacterial, may also lead to lower IgG2 levels as the body prioritizes other antibody types. Chronic illnesses or treatments that suppress the immune system can also affect antibody production.
How Often Should I Get This Test?
The frequency of this test depends on your medical condition and why it was ordered. If you have an ongoing immune-related issue, your doctor may recommend regular monitoring. For one-time concerns, like evaluating infection risk, it might be done only once or as needed.
Can Diet or Supplements Affect IgG2 Levels?
Diet and supplements can indirectly influence immune function, but they do not directly alter IgG2 antibody levels. A balanced diet rich in vitamins and minerals supports overall immune health, but specific foods or supplements are not known to directly raise or lower IgG2 levels. Always consult your doctor before making significant changes to your diet or supplement regimen.
  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 17, 2026. · Read our editorial policy