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Serum Immunoassay for Total Immunoglobulin G (IgG) Concentration

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 plays a key role in long-term immunity.

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
112036-9
Short code
Info to be requstd UGI Endscpy
Synonyms
Info to be requstd UGI Endscpy
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
endoscopy
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 abundant antibody in your blood. It’s produced by your immune system in response to infections and helps provide protection against diseases. This test helps doctors assess your immune function, especially if you have concerns about immune deficiencies or chronic infections.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like frequent infections, low energy, or if you’re being treated for conditions like HIV, lupus, or other immune-related disorders. It can also be part of monitoring for certain cancers or autoimmune diseases.

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 or have a history of bleeding, let your doctor know before the test.

What to Expect During the Test

The test involves drawing a small amount of blood from a vein in your arm. It usually takes a few minutes, and you may feel a slight pinch. The blood is then sent to a lab for analysis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Understanding IgG Levels

Short name

IgG Level

Frequently asked questions

How long will the results take to return?
Results are typically available within 1–3 business days, depending on your lab. Your doctor will discuss the results with you during your follow-up visit.
What do low IgG levels mean?
Low IgG levels may indicate an immune deficiency, where your body struggles to produce enough antibodies to fight infections. This can happen due to genetic conditions, certain medications, or chronic illnesses like HIV.
What do high IgG levels mean?
High IgG levels might suggest an overactive immune response, such as chronic infections, autoimmune diseases, or certain cancers. Your doctor will consider your overall health and symptoms to interpret the results.
  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