Skip to content

Serum or Plasma Mass Concentration of Immunoglobulin G (IgG) Substance

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

This test measures the amount of Immunoglobulin G (IgG), the most common type of antibody in your blood, using a blood sample.

Quick summary

["IgG helps protect your body from infections and supports immune function."]

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

Key facts at a glance

LOINC
86064-3
Short code
S pneum Da 23F IgG Ser-mCnc
Synonyms
S pneum Da 23F IgG Ser-mCnc
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 occur due to immune system issues, certain medical conditions, or after treatments like chemotherapy. It may also be used to monitor immune response in conditions like HIV, cancer, or autoimmune diseases.

How the Test Works

Blood is drawn from a vein, usually in your arm. The sample is then analyzed to determine the mass concentration of IgG in your serum or plasma using a specialized laboratory method.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours if your provider specifies. Wear comfortable clothing with easy arm access.

What to Expect During the Test

You’ll lie down while a healthcare provider inserts a small needle into your vein. A small amount of blood is collected into a vial or tube. The process is quick and typically painless, though you might feel a slight pinch.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Level

Frequently asked questions

Low IgG levels may indicate a weakened immune system, potentially due to conditions like HIV/AIDS, certain cancers, or long-term use of immunosuppressive medications. High IgG levels could suggest chronic infections, autoimmune diseases, or responses to vaccines.
IgG levels are often checked to diagnose or monitor conditions affecting immunity, such as primary immunodeficiency disorders, chronic infections, or after receiving immune-modifying treatments.
What does an abnormal IgG level mean?
An abnormal IgG level can signal an underlying health issue, such as an immune deficiency or chronic infection. Your provider will discuss the results with you and may recommend further testing or treatments based on the cause.
How often should I get this test?
Frequency depends on your medical condition and treatment plan. Your healthcare provider will determine how often you need this test based on your specific needs and health status.
  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