IgG Subclass 1 (Immunoglobulin G1) in Serum
This test measures the amount of Immunoglobulin G1 (IgG1), a type of antibody in your blood serum. IgG1 is part of your immune system and helps fight infections.
["IgG1 helps protect your body against bacteria and viruses by marking them for destruction."]
Key facts at a glance
- LOINC
- 103067-5
- Short code
- Wheat (rTri a) 19 IgE RAST
- Synonyms
- Wheat (rTri a) 19 IgE RAST
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- rast
- CPT
- 84484
- SNOMED
- 302774002
- 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 This Test Measure?
IgG1 is one of five subclasses of Immunoglobulin G (IgG), the most common antibody in your blood. IgG1 plays a key role in defending against a wide range of pathogens, including bacteria and viruses. This test specifically looks at the concentration of IgG1 antibodies in your serum sample, which can be useful in diagnosing or monitoring certain immune-related conditions.
Why Might You Need This Test?
Your healthcare provider may order this test if you have symptoms or conditions that could be linked to changes in IgG1 levels, such as recurrent infections, autoimmune diseases, or immune deficiencies. It may also be part of a broader evaluation for conditions affecting antibody production or function.
What Does a Result Mean?
Results are typically reported as a concentration value (e.g., grams per liter). While reference ranges can vary by lab, abnormal levels may suggest issues like low immune function, certain infections, or immune system disorders. Your doctor will interpret the result in the context of your overall health and medical history.
How Is This Test Done?
A blood sample is drawn from a vein, usually in your arm. The blood is then sent to a lab for analysis. The test measures IgG1 antibodies using a method such as nephelometry or immunoturbidimetry, which detects the presence and concentration of these antibodies in your serum.
Reference range
Adult: 10-40 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.
◆Associated findings1
Short name
IgG1 Level
Frequently asked questions
What causes IgG1 levels to change?
What are common conditions linked to abnormal IgG1 levels?
Can lifestyle or diet affect IgG1 levels?
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 17, 2026. · Read our editorial policy