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

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

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

Quick summary

["IgG levels help assess your immune system’s strength and detect potential deficiencies or immune-related conditions."]

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

Key facts at a glance

LOINC
36082-6
Short code
MRA IVC
Synonyms
MRA IVC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr-angio
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 the most common type of antibody in your blood. It plays a key role in fighting off infections, including bacteria and viruses. Your body produces IgG in response to vaccines, infections, or exposure to foreign substances. Low levels may indicate a weakened immune system, while high levels could suggest chronic infection or certain immune disorders.

Why Might You Need This Test?

Your doctor may order an IgG test to check for immune system issues, such as: - Severe combined immunodeficiency (SCID) - Common variable immunodeficiency (CVI) - Chronic infections (e.g., HIV, hepatitis) - After receiving certain vaccines or treatments that boost immunity. It can also help monitor immune responses in people with autoimmune diseases.

How Is the Test Done?

A blood sample is taken from a vein in your arm. The blood is sent to a lab, where it is analyzed using nephelometry, a method that measures how particles in the blood scatter light to determine IgG concentration.

What Do the Results Mean?

Results are compared to standard ranges for healthy adults. Low IgG levels may require further evaluation for immune deficiencies or conditions affecting antibody production. High levels could signal chronic infections or immune system overactivity. Your doctor will interpret results in the context of your medical history and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Level

Frequently asked questions

What causes low IgG levels?
Low IgG levels can be caused by: - Primary immune deficiencies (e.g., SCID, CVI) - Chronic illnesses (e.g., HIV, kidney disease) - Certain medications or treatments that suppress the immune system - Malabsorption issues (e.g., celiac disease) that prevent proper nutrient absorption. Always discuss symptoms with your doctor, as underlying causes vary.
What are the most common symptoms of low IgG?
Symptoms of low IgG may include: - Frequent or severe infections (e.g., pneumonia, sinus infections) - Slow wound healing - Recurring ear or respiratory infections - Chronic diarrhea or digestive issues If you experience these symptoms, mention them to your doctor, as they may relate to immune function.
Can high IgG levels be harmful?
High IgG levels are less common but may indicate: - Chronic infections (e.g., long-term bacterial or viral infections) - Autoimmune diseases (e.g., rheumatoid arthritis, lupus) - Certain cancers (e.g., multiple myeloma) Your doctor will evaluate results alongside your medical history to determine if further testing is needed.
  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