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Serum Immunoassay for Immunoglobulin G (IgG) Substance Content

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

This test measures the amount of Immunoglobulin G (IgG), a type of antibody in your blood, which helps fight infections and supports immune function.

Quick summary

["IgG helps protect your body against diseases and infections."]

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

Key facts at a glance

LOINC
95688-8
Short code
DENV1+2+3+4 IgM Spec Ql IA
Synonyms
DENV1+2+3+4 IgM Spec Ql IA
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

Why This Test Might Be Ordered

Your healthcare provider may order this test to check for low or high levels of IgG, which can occur due to immune system conditions, infections, or certain medical treatments. It may also be used to monitor immune function in people with chronic illnesses or after receiving immune-boosting therapies.

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, which usually takes a few minutes. If you’re on blood thinners or have a history of bleeding issues, let your provider know beforehand.

How the Test Results Are Interpreted

Results are compared to a general reference range for healthy adults. Very low IgG levels may suggest immune deficiencies, while very high levels could indicate chronic infections, autoimmune diseases, or certain cancers. Your provider will discuss these results with you in detail.

Common Conditions Affecting IgG Levels

Conditions like HIV/AIDS, certain autoimmune diseases (e.g., lupus), or long-term infections can alter IgG levels. Children with congenital immune disorders or those receiving certain medications may also have abnormal IgG results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

What causes IgG levels to be low?
Low IgG levels can result from immune system disorders (e.g., primary immunodeficiency), chronic illnesses (e.g., HIV), certain medications, or conditions affecting nutrient absorption (e.g., celiac disease). It may also occur in newborns or premature infants due to incomplete immune development.
What does it mean if my IgG levels are high?
High IgG levels can be due to chronic infections, autoimmune diseases (e.g., rheumatoid arthritis), or certain cancers. In some cases, it may reflect an overactive immune response, though this isn’t always straightforward to diagnose. Your provider will review your medical history and other test results to determine the cause.
How often should I get this test?
The frequency depends on your health condition. If you have an immune-related disorder, your provider may recommend regular monitoring. Otherwise, this test is often done only when symptoms or other test results suggest a need for evaluation.
  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