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Total Serum Immunoglobulin G (IgG) Level

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

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

Quick summary

["IgG helps protect your body from illness and infection by identifying and neutralizing harmful substances."]

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

Key facts at a glance

LOINC
60522-0
Short code
BORHM
Synonyms
B hermsii IgG+IgM Ser Ql
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or red-top tube without anticoagulant
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Immunofluorescence Assay (IFA) or Enzyme Immunoassay (EIA)
CPT
86618
SNOMED
31618003
Specimen volume
1-2 mL of serum
Stability
Stable at room temperature for 24 hours; refrigerated (2-8°C) for 7 days; frozen (-20°C or below) for up to 30 days. Avoid repeated freeze-thaw cycles.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
24–72 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may order this test to check if your immune system is working properly. It can help diagnose or monitor conditions like low immunity, autoimmune diseases, infections, or certain blood disorders. It may also be used to evaluate responses to treatments or vaccinations.

What to Expect Before the Test

No special preparation is usually needed. You may have a small needle inserted into your arm to draw blood. If you’re on blood thinners, let your provider know before the test.

What the Test Results Mean

IgG levels can vary based on age, overall health, and medical conditions. High levels might indicate overactive immune response or certain infections. Low levels could suggest weakened immunity, chronic illnesses, or conditions like HIV or severe malnutrition.

Common Conditions Affecting IgG Levels

IgG levels can be affected by conditions like chronic infections, autoimmune diseases (e.g., lupus or rheumatoid arthritis), certain cancers, or immune system disorders. It may also be checked after vaccination to see if your body produced enough antibodies.

Reference range

NegativeN/A

Specimen: serum

No special patient preparation required. Sample should be collected before initiation of antibiotic therapy when possible, as early antibiotic use may affect antibody response.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Level

Frequently asked questions

What does it mean if my IgG level is too high or too low?
High IgG levels may suggest an overactive immune response, chronic infections, or certain inflammatory conditions. Low IgG levels often point to a weakened immune system, which could be due to genetic disorders, chronic illnesses, or conditions like HIV. Always discuss your results with your healthcare provider for personalized interpretation.
How often should I get this test?
The frequency depends on your health condition and why the test was ordered. Your healthcare provider will determine the best schedule based on your needs, such as monitoring treatment progress or managing chronic illnesses.
Can diet or lifestyle affect IgG levels?
Diet and lifestyle factors like nutrition, stress, and overall health can influence immune function, but IgG levels are primarily measured in blood. While diet can support immune health, it doesn’t directly alter IgG test results. Always follow your provider’s advice for managing your health.
  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