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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. IgG helps protect your body from infections and diseases.

Quick summary

["IgG antibodies play a key role in long-term immunity."]

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

Key facts at a glance

LOINC
48070-7
Short code
HBV surface IgG Ser Ql IA
Synonyms
HBV surface IgG Ser 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
86430
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 Does This Test Measure?

IgG is the most common type of antibody in your blood. It’s produced by your immune system to fight off bacteria and viruses. This test helps doctors assess your immune response, check for infections, or evaluate conditions like immune deficiencies or autoimmune diseases.

Why Might You Need This Test?

Your doctor may order an IgG test if you have symptoms of infection, if you’re recovering from an illness, or if you have a condition that affects your immune system, such as HIV, lupus, or certain cancers. It can also be used to monitor treatment effectiveness for immune-related disorders.

What to Expect Before the Test

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

What to Expect During the Test

The blood sample is collected in a tube and sent to a lab for analysis. The test typically takes a few minutes, and you may feel a slight pinch or discomfort during the draw.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

How long does it take to get the results?
Results are usually available within 1 to 3 business days, depending on your lab’s processing time.
What does it mean if my IgG level is low?
A low IgG level could mean your immune system isn’t working as well as it should, which might require further evaluation by your doctor to determine the cause.
Can diet affect IgG levels?
While diet can influence overall immune function, IgG levels are primarily determined by your body’s immune response and health status. Your doctor may recommend dietary changes if related conditions (like malabsorption) are suspected.
  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