IgG Subclass Testing
The what and why of IgG Subclass Testing
June 20, 2023 by Jeffery Cuneo
An IgG Subclasses lab test is a blood test that measures the levels of the four subclasses of IgG antibodies: IgG1, IgG2, IgG3, and IgG4. IgG antibodies are the most common type of antibodies in the blood and they help protect the body from infections and other diseases.
The purpose of an IgG Subclasses lab test is to help diagnose and monitor certain conditions that affect the immune system, such as antibody deficiency, autoimmune diseases, and IgG4-related disease. The test can also help evaluate the response to vaccination or immunotherapy.
The normal ranges of IgG Subclasses vary depending on the age, gender, and method of the laboratory. View our reference intervals here.
Low levels of one or more IgG Subclasses may indicate a partial or selective antibody deficiency, which means the body cannot produce enough antibodies to fight certain types of infections. This can increase the risk of recurrent or chronic infections, especially in the respiratory tract, sinuses, ears, and lungs. Some causes of low IgG Subclasses include genetic disorders, viral infections, medications, malnutrition, and aging.
High levels of one or more IgG Subclasses may indicate an overactive immune system, which means the body produces too many antibodies that may attack its own tissues or organs. This can lead to inflammation and damage in various parts of the body, such as the pancreas, salivary glands, kidneys, lungs, and skin. Some causes of high IgG Subclasses include autoimmune diseases, chronic infections, allergies, and cancer.
If you have any questions or concerns about your IgG Subclasses lab test results, please consult your doctor or health care provider. They can explain what your results mean and how they relate to your condition and treatment plan.