Immunoglobulins Igg Subclasses Immunoassay Blood

Immunoglobulins IgG Subclass Immunoassay Blood test helps to check whether an individual is having specific IgG subclass deficiencies or not.

What are Immunoglobulins and their types?

Antibodies are the protective proteins produced by the immune system and known as immunoglobulins Ig. Antibodies are produced when any foreign substance or virus or bacteria enters the body. These foreign substances are known as antigens. Antibodies recognize and attach to the antigens in order to remove them from the body. There are five (5) subtypes of antibodies and they are IgG, IgM, IgA, IgD, IgE.

IgG provides long-term protection as it presents in the circulation for long period after the presence of an antigen. IgM enhances the ingestion of cells by phagocytosis. IgA is also the first defense for intestine, lungs, and nose. They bind antigens to the microbes before they invade tissues and keeps antigens in secretion and when secretion is expelled, antigens are also expelled. IgD helps in the induction of antibody production and presents on the surface of B-cells. IgE binds to the basophils and mast cells.

What are IgG Immunoglobulin G Subclasses?

Immunoglobulin IgG class of antibodies are of 4 types and they are IgG1, IgG2, IgG3, and IgG4. IgG1 and IgG3 subclasses have antibodies against bacterial toxins and viral proteins. IgG2 subclass has antibodies against the sugar coated disease-causing bacteria. The percentage of IgG subclasses in the blood varies with the age group.

Why this test is performed?

The doctor may ask you to undergo this test if you are suffering from symptoms such as chronic diarrhea, vomiting, shortness of breath, weakness, recurrent fever, coughing, loss of energy, severe abdominal pain, indigestion, ear infection, sore throat, etc. This test is also done if an individual is suffering from recurrent upper and lower respiratory infections, gastrointestinal infections and recurrent viral infections.

If an individual is on the treatment for immunodeficiency Immune system to fight against infections is absent or not working then the doctor may ask to perform this test to evaluate and to check the effectiveness of the treatment.

How often this test should be performed?

If you have been diagnosed with immunodeficiency, your doctor may advise you to get this test done once in a year based on your clinical condition. If you are a healthy individual above the age of 35, your doctor may advise you to undergo this test either on a yearly basis or every other year.

Precautions:

Some medications may change the levels of IgG in the blood and hence you are advised to inform all your current medications to the doctor prior to the test. Rheumatoid factor can give rise to false positive results.

If the test results of IgG1 subclass are lower than the normal range, then it may indicate that the individual is suffering from hypogammaglobulinemia.

If the test results of IgG2 and IgG3 subclass are lower than the normal range with normal total IgG levels, then it may indicate that the individual is suffering from specific antibody deficiency with normal IgG.

IgG4 subclass of Immunoglobulin G is available at very low levels. So, IgG4 may be undetectable in the blood of many adults and hence, IgG4 levels alone are not sufficient for diagnosing the antibody deficiency.