The blood antibody tests are done on the blood sample of a person either for qualitative diagnosis, to determine the presence or absence of particular antibodies in the sample or for quantitative diagnosis, to determine the amount of particular antibody in the sample. Immunoglobulin proteins also known as Antibodies are released in the body by immune system in response to foreign substances like virus, bacteria and toxins.
The red blood cells have antigens attached at the tips. Each antibody structure is unique and recognizes an antigen. The antibody attaches to antigen to form immune complex, which is instrumental in killing the infectious agent. There are five different classes of immunoglobulin proteins which are IgA, IgD, IgE, IgG and IgM, each serving a different function. The blood antibody tests mainly measure the quantities of IgE, IgG and IgM immunoglobulin proteins.
The primary immune response against a new pathogen is elicited by IgM immunoglobulin though it might take up to two weeks for the immune system to start producing antibodies against new antigen. The body develops IgG immunoglobulin using IgM Memory. The second time if the same pathogen enters the body then there will be a stronger immune response mainly from IgG which are synthesized in large volumes.
Purpose of Blood Antibody Tests
The blood antibody tests are sure a good measure of diagnosis of disease in a person. If an antibody is found in a person it indicates that the person is either suffering or previously had an outbreak of the disease. The blood antibody tests are accurate and diagnose a lot of medical conditions.
- Autoimmune diseases : Sometimes the immune system is not able to distinguish between the foreign substances and body’s own antigens. It then produces auto-antibodies that try to kill the body’s parts. It can either affect a single organ or multiple organs. Blood antibody tests diagnose such autoimmune disease like Addison’s disease and thyroid disorders etc by identifying the antibodies.
- Blood Transfusions & Organ Transplants : Matching the blood type for antigens before any blood transfusion and organ transplant is highly imperative else the immune system can trigger an immune response to kill the transfused blood cells and organ. The blood antibody tests are done immediately after blood transfusion or organ transplants to check for any blood transfusion reaction or antibodies against the transplanted organ.
- Allergies : Many foreign substances are non-harmful to the body and go without any immune response in most people however; in some persons the immune system might get activated producing antibodies. Such conditions are known as allergies and mainly involve IgE antibodies. The blood antibody tests measure the quantity and type of IgE antibodies to identify the type of allergies.