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Immunoglobulin G (IgG) in Serum by Latex Agglutination (Screening)

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

This test measures the level of Immunoglobulin G (IgG), the most common type of antibody in your blood. IgG helps protect your body from infections and is important for long-term immunity.

Quick summary

["IgG antibodies are vital for fighting infections and maintaining immunity, and this screening helps monitor their presence in your bloodstream."]

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

Key facts at a glance

LOINC
27231-0
Short code
Deprecated S pneum23 IgG Ser IA-mCnc
Synonyms
Deprecated S pneum23 IgG Ser IA-mCnc
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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

What Does This Test Measure?

IgG is a type of antibody produced by your immune system to help fight off infections. This test checks for the concentration of IgG in your serum, which can indicate your immune response or potential deficiencies.

Why Might You Need This Test?

Your doctor may order this test to assess your immune system function, evaluate immune-related conditions, screen for infections, or monitor treatment responses in conditions like immunodeficiency or autoimmune diseases.

When Is This Test Typically Done?

This screening test is often performed as part of routine blood work, during diagnostic evaluations for immune disorders, before certain vaccinations, or to monitor chronic conditions affecting immunity.

What Does a Low or High IgG Level Mean?

Low IgG levels may suggest an immune deficiency or poor absorption of nutrients, while high levels could indicate chronic infections, autoimmune responses, or other underlying health issues. Results are interpreted by your healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Screening

Frequently asked questions

What Are Common Causes of Abnormal IgG Levels?
IgG levels can be affected by infections (like chronic bacterial or viral infections), autoimmune diseases, malnutrition, or certain medications. Genetic factors and immune system disorders may also influence IgG production.
How Is This Test Performed?
A blood sample is drawn from a vein, usually in your arm. The serum (liquid part of blood after clotting) is then tested using a latex agglutination method to detect IgG antibodies.
How Long Does It Take to Get Results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the findings with you.
  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