Skip to content

Immunoglobulin G (IgG) Subclass 2 in Serum or Plasma

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

This test measures the amount of Immunoglobulin G (IgG) subclass 2, a type of antibody in your blood. IgG antibodies help fight infections and are important for long-term immunity.

Quick summary

["IgG2 helps protect against certain bacteria and viruses, and its levels can indicate immune function."]

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

Key facts at a glance

LOINC
97766-0
Short code
IgG2 Fld-mCnc
Synonyms
IgG2 Fld-mCnc
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 Might This Test Be Ordered?

Your healthcare provider may order this test if you have symptoms of a weakened immune system, such as frequent infections, trouble fighting off certain types of bacteria, or if you’re being evaluated for conditions like recurrent sinus infections, pneumonia, or certain autoimmune diseases. It may also be part of a broader immune evaluation.

What Does the Test Measure?

IgG2 is one of five subclasses of IgG antibodies. While IgG is the most common antibody in your blood, IgG2 specifically plays a role in defending against some bacterial infections. Low levels may suggest immune deficiencies or certain immune disorders.

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 blood, similar to a routine blood draw. If you’re concerned about needles or blood, let your provider know.

What the Results Mean

Results are compared to a general range for healthy adults, but individual ranges can vary. Low IgG2 levels may indicate an immune system that struggles to produce enough antibodies for certain infections. High levels might be seen in some chronic infections or certain immune responses.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG2 Level

Frequently asked questions

How often will I need this test?
This test is typically ordered as part of an evaluation, not routinely unless you have symptoms or a known condition affecting your immune system. Your provider will determine how often follow-up tests are needed based on your health and results.
What are the most common causes of low IgG2 levels?
Low IgG2 levels can be caused by primary immune deficiencies (like Common Variable Immunodeficiency), certain autoimmune diseases, or conditions that affect antibody production, such as HIV/AIDS or chemotherapy treatments.
Can I take anything before the blood draw?
You can eat and drink normally before the test, but avoid heavy meals just before drawing blood to minimize discomfort. If you’re on medications, let your provider know as some may affect 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