The five major types of antibodies are…

 IgA antibodies are found in areas of the body such as: the respiratry tract, digestive tract, ears, eyes, and genitalia.  IgA’s protect body surfaces that are exposed to outside substances. This type of antibody is also found in different body fluids (saliva, tears and blood). About 10 – 15 percent of the antibodies present in the body are IgA antibodies. A small number of people do not make IgA antibodies.

IgG antibodies are found in all body fluids. They are the most common antibody 75 – 80 percent of all the antibodies in the body. IgG antibodies are important in fighting bacterial and viral infections. IgG antibodies are the only type of antibody that can cross the placenta in a pregnant woman to help protect the fetus. 

IgM antibodies are the largest antibody. They are found in blood and lymph fluid. They are the first type of antibody made in response to any infection. They cause other immune system cells to attack foreign substances. IgM antibodies are about 5 – 10 percent of all antibodies in the body.

IgE antibodies are found in the pulmonary system, integumentary system, and mucous membranes. They cause the body to react against foreign substances such as pollen, fungus spores, and dander. They may show up in allergic reactions to food, medications, and poisons. IgE antibody levels are often high in people with allergies. 

IgD antibodies are found in small amounts in tissues that line the abdomen and chest. It is not clear how exactly they work.

levels of different antibodies can give your doctor information about what is causing a health issue.

Immunoglobulins in the blood are tested to help…

• Find autoimmune diseases and allergies.
• Find cancers.
• Identify if recurring infections are caused by low levels of immunoglobulins (especially IgG).
• Check treatment for certain types of cancer affecting the bone marrow.
• Check treatment for Helicobacter pylori.
• Check responses to immunizations and see if you are immune to a particular disease.