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Immunoglobulin G (IgG) concentration in serum/plasma

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 levels help assess immune function and identify potential deficiencies or excesses."]

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

Key facts at a glance

LOINC
14013-7
Short code
PA IgM Bld FC-aCnc
Synonyms
PA IgM Bld FC-aCnc
Category
hematology
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Is IgG Used For?

IgG is the primary antibody your immune system produces to fight off bacteria and viruses. It plays a crucial role in long-term immunity, helping your body remember past infections and respond more quickly if you encounter the same pathogen again. Levels of IgG can indicate whether your immune system is functioning properly or if there may be an underlying condition affecting antibody production.

Why Might You Need This Test?

Your healthcare provider may order an IgG test if you have symptoms of a weakened immune system, such as frequent infections, slow wound healing, or recurrent infections in areas like the sinuses, lungs, or urinary tract. It may also be used to monitor conditions like HIV, certain autoimmune diseases, or after treatments that weaken the immune system, such as chemotherapy.

What to Expect Before the Test

No special preparation is usually needed for this test. You may have a small needle inserted into a vein in your arm to draw a blood sample. If you are nervous about needles, let your healthcare provider know so they can offer alternatives or support.

What Happens During the Test?

A healthcare professional will clean the area with an antiseptic solution and insert a needle into your vein. Blood will be collected into a tube, and the needle will be removed. You may feel a slight pinch or sting, but the procedure usually takes just a few minutes. You can usually resume normal activities immediately after.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Level

Frequently asked questions

What Are Normal IgG Levels?
Normal IgG levels vary slightly between individuals and labs, but they generally fall within a range that indicates adequate immune function. Low IgG levels may suggest an immune deficiency, while very high levels could indicate chronic infections, certain autoimmune diseases, or other conditions. Your results will be interpreted by your healthcare provider in the context of your overall health and medical history.
How Often Should I Get This Test?
The frequency of IgG testing depends on your health condition and medical needs. If you have a known immune deficiency or are undergoing treatment that affects your immune system, your provider may recommend regular monitoring. Otherwise, this test is often done only when symptoms or concerns suggest it is necessary.
Can Diet or Lifestyle Affect IgG Levels?
Diet and lifestyle factors like nutrition, stress, and overall health can influence immune function, but they do not directly affect IgG levels. Eating a balanced diet rich in vitamins and minerals, managing stress, and staying hydrated can support your immune system, but IgG levels are primarily determined by your body’s immune response.
  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