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Total Mass Fraction of Immunoglobulin G in Serum/Plasma

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

This test measures the overall amount of Immunoglobulin G (IgG), a key antibody protein in your blood that helps fight infections.

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
68974-5
Short code
IgG.IT/IgG.total MFr CSF
Synonyms
IgG.IT/IgG.total MFr CSF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Ref low
8
Ref high
61
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82977
SNOMED
3110003
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to evaluate your immune system, diagnose conditions like immunodeficiency, or monitor treatment for diseases such as lupus or multiple sclerosis. It can also help check for infections or determine if you have enough antibodies to protect against certain illnesses.

What Does a Low or High IgG Level Mean?

Low IgG levels may indicate an immune system that doesn’t work well, increasing your risk of infections. High levels could suggest chronic inflammation, autoimmune diseases, or other conditions that cause the body to produce extra antibodies.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is then separated into serum or plasma for testing. This test does not require fasting.

Common Conditions Monitored or Diagnosed

IgG levels are often checked in people with suspected immune disorders, those receiving immune-suppressing treatments, or individuals with frequent infections. It can also be part of screening for genetic or congenital immune deficiencies.

Reference range

Adult males: 8-61 U/L; Adult females: 5-36 U/LN/A

Specimen: csf

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: IgG is the most abundant antibody in the blood and plays a vital role in long-term immunity. Abnormal levels can signal underlying immune dysfunction, chronic disease, or the body’s response to certain treatments.

Short name

IgG Total

Frequently asked questions

What does a normal IgG level mean for my health?
A normal IgG level generally means your immune system is functioning adequately to produce enough antibodies to protect you from infections. However, individual reference ranges can vary, and your healthcare provider will interpret results 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 medical condition and treatment plan. Your doctor will determine how often you need this test based on your specific needs, such as monitoring an immune disorder or managing a chronic illness.
Can lifestyle or diet affect IgG levels?
While diet and lifestyle factors like nutrition and stress can influence immune function, they do not directly alter IgG levels. Maintaining a balanced diet rich in vitamins and minerals can support overall immune health, but this test specifically measures the amount of IgG antibodies in your blood.
  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