The Immunoglobulins Blood Test, Quantitative, IgA, IgG, and IgM screens for:
- Immunoglobulin A
- Immunoglobulin G
- Immunoglobulin M
What is the purpose of this test?
Order this Immunoglobulins Blood Test, QN, IgA, IgG, and IgM to measure immunoglobulin (IgG, IgA, and IgM) levels in the blood to assess the immune system status and detect or monitor a deficiency or excess. Immunoglobulins, commonly known as antibodies, are vital to the body's immune system. These immunoglobulins are proteins produced by plasma cells in the immune system as a response to harmful antigens (bacteria or viruses) that cause infections or illnesses.
When an individual becomes infected or exposed to an antigen, their immune system recognizes the microorganism or substance as foreign. As a result, it stimulates the plasma cells to produce specific immunoglobulins (antibodies) that combat the invaders. Suppose the individual is exposed to the antigen again. In that case, the immune system "recognizes" the antigen encountered, which allows for the immediate production of more antibodies to help stop re-infection.
What does this test measure?
This Immunoglobulins Blood Test screens for three main types of immunoglobulins. Each type represents a group of antibodies and has a somewhat different function. These three types of immunoglobulins include:
- Immunoglobulin A (IgA) – IgA is found primarily in the walls of the respiratory and digestive tract and in saliva, tears, and breast milk. IgA's primary function is to protect against infection in mucosal areas of the body, such as the sinus, lungs, stomach, and intestines. There are two IgA subtypes: IgA1 and IgA2.
- Immunoglobulin G (IgG) – IgG is mainly found in the blood. IgG antibodies are produced in response to an active infection or recent exposure to an antigen. IgG antibody levels peak a few weeks after the infection begins, then decrease and stabilize. The body maintains a certain level of IgG antibodies that can be instantly produced once exposed to the same antigen again, creating long-term protection against infections. Vaccinations replicate this process by exposing individuals to weakened IgG antibodies and stimulating antigen recognition. There are four IgG subtypes: IgG1, IgG2, IgG3, and IgG4.
- Immunoglobulin M (IgM) – IgM is the first antibody produced by the immune system as a response to a new infection or a new foreign antigen, providing only short-term protection. They increase for several weeks and then decline as the immune system produces IgG antibodies.
What causes an immunoglobulins deficiency or excess?
Individuals may acquire an immunoglobulins deficiency through an underlying condition, usage of certain medications, or other contributing factors that prevent immunoglobulin production. In addition, a deficiency may be inherited through a rare genetic disorder. The following conditions are associated with an immunoglobulins deficiency:
- Kidney disease
- Diabetes
- Nephrotic syndrome
- Usage of immunosuppressant drugs, phenytoin, and carbamazepine
- Short-term developmental delay in premature infants
- Gastrointestinal issues that affect digestion or absorption of proteins
However, an individual may also experience an excess of all three (polyclonal increase) immunoglobulins or a specific immunoglobulin (monoclonal increase) due to several conditions. The following conditions are related to excessive immunoglobulin levels:
- Acute or chronic infections
- Autoimmune disorders
- Cirrhosis
- Inflammatory disorders
- Hyperimmunization reactions
- Wiskott-Aldrich syndrome
- Congenital infection (syphilis, toxoplasmosis, rubella, CMV)
- Multiple myeloma
- Chronic lymphocytic leukemia (CLL)
- MGUS (monoclonal gammopathy of undetermined significance)
- Lymphoma
- Waldenstrom's macroglobulinemia
