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Immunoglobulin G (IgG) in serum/plasma by nephelometry

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. IgG helps protect your body from infections and diseases.

Quick summary

["IgG helps fight infections and supports immune function."]

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

Key facts at a glance

LOINC
93744-1
Short code
HTLV I+II IgG Pnl CSF
Synonyms
HTLV I+II IgG Pnl CSF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What Does This Test Measure?

IgG is the primary antibody produced by your immune system in response to infections, vaccines, and other immune challenges. It circulates in your bloodstream and provides long-term protection against pathogens like bacteria and viruses. Your body produces IgG throughout your life, and levels can vary based on immune activity, health conditions, and exposure to infections.

Why Might You Need This Test?

Doctors may order an IgG test to evaluate your immune system’s ability to fight infections, diagnose conditions like immunodeficiency, assess the effectiveness of treatments for autoimmune diseases, or check for antibody deficiencies in newborns or individuals with chronic illnesses.

Common Reasons for Testing

Common reasons include monitoring immune function in patients with HIV/AIDS, checking for low IgG levels in infants or children, evaluating immune responses after vaccination, or diagnosing conditions like common variable immunodeficiency (CVID).

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The sample is then sent to a lab where it is analyzed using nephelometry, a technique that measures the scattering of light to determine the concentration of IgG in your serum or plasma.

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 can vary slightly between labs, but they generally fall within a range that reflects typical immune function. Low IgG levels may indicate an immune deficiency, while very high levels could suggest chronic infections, autoimmune diseases, or other health conditions.
How Often Should I Get This Test?
The frequency of IgG testing depends on your medical history, symptoms, and reasons for testing. Your healthcare provider will determine the best schedule based on your individual needs, such as monitoring immune function over time or responding to specific treatments.
Can Diet or Lifestyle Affect IgG Levels?
Diet and lifestyle factors like nutrition, stress, and overall health can influence immune function, but they typically do not directly alter IgG levels. Maintaining a balanced diet rich in vitamins and minerals can support immune health, but IgG levels are primarily determined by your immune system’s response to infections and immune activity.
  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