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Total Immunoglobulin G (IgG) in Serum

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 is one of the most common antibodies found in the blood.

Quick summary

["IgG helps fight infections and supports long-term immunity."]

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

Key facts at a glance

LOINC
96501-2
Short code
TIF1-gamma Ab Ser IA-aCnc
Synonyms
TIF1-gamma Ab Ser IA-aCnc
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
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 happen due to immune system issues, certain medical conditions, or after treatments like chemotherapy. It can also be used to monitor immune function in people with chronic illnesses or those who have received immune-modifying 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 a blood sample. If you’re anxious about needles, let your healthcare provider know so they can offer options like numbing cream or a different vein.

What to Expect During the Test

The blood sample will be taken from a vein in your arm. You may feel a slight pinch when the needle is inserted, but the process usually takes only a few minutes. The blood will be sent to a lab for analysis.

Results and Follow-Up

Results are typically reported as a mass concentration in grams per liter (g/L). Your results will be reviewed by a healthcare professional, who will discuss them with you based on your medical history and symptoms. Follow-up may include additional tests or treatments if needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Low IgG levels can indicate weakened immunity, which may lead to frequent infections, delayed wound healing, or autoimmune conditions. High IgG levels might suggest chronic infections, certain immune disorders, or overproduction of antibodies. Monitoring IgG levels helps diagnose and manage conditions like HIV, lupus, or immune deficiencies.

Short name

IgG Level

Frequently asked questions

What does a low IgG level mean?
A low IgG level may mean your immune system isn’t producing enough antibodies to fight infections effectively. This could be due to an immune disorder, certain medications, or conditions like HIV or malnutrition. Your doctor may recommend treatments to boost your immune response or further tests to understand the cause.
What does a high IgG level mean?
High IgG levels might indicate chronic infections, autoimmune diseases, or conditions like multiple myeloma, where the body produces too many antibodies. It can also be seen in response to long-term inflammation or certain immune disorders. Your doctor will work with you to determine the best course of action.
Can IgG levels change over time?
Yes, IgG levels can fluctuate due to infections, immune responses, treatments (like chemotherapy), or underlying health conditions. Regular monitoring may be needed if you have a chronic illness or are undergoing treatments that affect immunity. Your doctor will discuss any changes with you based on your specific situation.
  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