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Serum or plasma mass concentration of immunoglobulin G (IgG) by nephelometry

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

This test measures the amount of Immunoglobulin G (IgG), the most common type of antibody in your blood. IgG helps protect your body from infections and diseases.

Quick summary

["IgG supports your immune system’s defense against pathogens like bacteria and viruses."]

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

Key facts at a glance

LOINC
60466-0
Short code
N men sg Y IgG Ser IA-mCnc
Synonyms
N men sg Y IgG Ser IA-mCnc
Category
chemistry
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 Is Immunoglobulin G (IgG)?

IgG is a type of protein (antibody) produced by your immune system. It plays a key role in fighting infections and helping your body remember past illnesses. IgG is found in large amounts in your blood and helps protect you from diseases by neutralizing toxins and viruses.

Why Might You Need This Test?

Doctors may order an IgG test to check for low or high levels, which can happen due to immune system issues, certain medical conditions, or after treatments like chemotherapy. It can also help diagnose or monitor conditions like infections, autoimmune diseases, or immune deficiencies.

When Could You Expect Results?

Results are typically ready within 24 to 48 hours after your blood sample is drawn. Your healthcare provider will discuss the results with you during your follow-up visit.

How Is the Test Done?

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it usually doesn’t cause much discomfort. The blood is then sent to a lab for testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

What does an abnormal IgG level mean?
Low IgG levels may indicate a weakened immune system, which can make you more susceptible to infections. This can happen in conditions like HIV/AIDS, certain cancers, or after treatments that suppress the immune system. High IgG levels can sometimes be seen in chronic infections, autoimmune diseases, or certain types of cancer.
How often should I get this test?
Your doctor will determine the best timing for retesting based on your medical history, symptoms, and treatment plan. Regular monitoring may be needed if you have an ongoing condition that affects your immune system.
Can I prepare for this test?
No special preparation is needed for this blood test. However, avoid eating or drinking anything (except water) for a few hours before your appointment if instructed by your doctor.
  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