Serum or Plasma Immunoassay for Immunoglobulin G (IgG) Subclass 1 (IgG1)
This test measures the amount of Immunoglobulin G (IgG), a type of antibody, specifically the IgG1 subclass in your blood. IgG1 is one of the main types of antibodies your immune system produces to fight infections.
["IgG1 helps protect against bacterial and viral infections and plays a role in immune responses."]
Key facts at a glance
- LOINC
- 96487-4
- Short code
- NIF IgG Titr Ser IF
- Synonyms
- NIF IgG Titr Ser IF
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 8
- Ref high
- 61
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- if
- CPT
- 82977
- SNOMED
- 3110003
- 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 IgG1 Serve in the Body?
IgG1 antibodies are crucial for long-term immunity. They bind to pathogens (like bacteria and viruses) to mark them for destruction by other immune cells and can cross the placenta to provide passive immunity to a fetus. This subclass is particularly active in neutralizing toxins and enhancing immune responses to vaccines.
Why Might Your Doctor Order This Test?
Your doctor may request an IgG1 test if you have symptoms or conditions linked to immune system dysfunction, such as chronic infections, autoimmune diseases, or deficiencies in certain antibody classes. It may also be used to monitor treatment effectiveness in patients with immune-related conditions.
Common Conditions or Situations
IgG1 testing is often considered when diagnosing or managing conditions like recurrent infections, certain autoimmune diseases (e.g., rheumatoid arthritis), or immune deficiencies. It can also be part of a broader antibody profile to assess immune function.
What to Expect Before the Test
No special preparation is needed for this test. You’ll have a small needle inserted into your arm to draw blood. It usually takes a few minutes, and you may feel a brief pinch. If you have a hard time with blood draws, let your healthcare provider know in advance.
Reference range
Adult males: 8-61 U/L; Adult females: 5-36 U/LN/A
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: IgG1 Levels Can Provide Insights Into Immune Function and Disease Activity
Short name
IgG1 Level
Frequently asked questions
What Are Normal IgG1 Levels?
How Might Abnormally Low IgG1 Levels Affect Me?
What If My IgG1 Levels Are Higher Than Expected?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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