What is IgE?
Total IgE test, also known as quantitative IgE test, measures the quantity of immunoglobulin E (IgE) in the blood. When you have an allergy, your immune system regards a foreign substance, such as dust or pollen, as a threat. Your immune system fights against this threat by producing antibodies called IgE.
While total IgE test measures the overall number of IgE antibodies in your blood, another type of test called a specific IgE test tells you the quantity of IgE antibodies in response to a particular allergen.
Why is IgE done?
In case of symptoms of allergies
In case of doubt of parasitic infection
To evaluate children having a family history of allergies
To evaluate in case of suspected allergic respiratory disease
To confirm sensitivity to foods in patients of asthma, angioedema, or cutaneous disease
To evaluate sensitivity to insect venom allergens
What does IgE Measure?
IgE test measures the amount of IgE (immunoglobulin E) in the blood. It is an antibody produced by the immune system in response to danger. Normally, it is present in very small amounts in the blood. It belongs to the class of immunoglobulins which include five types of immunoglobulins: IgA, IgG, IgM, IgD, and IgE.
Immunoglobulins are produced by plasma cells (specific immune cells) when the body recognizes bacteria, viruses, other microorganisms or any other unknown substances as harmful foreign antigens to the immune system.
The production of IgE is seen in cases of response to allergens such as asthma and response to parasitic infections. Other allergens can include plant pollen, eggs, peanuts, bee venom, strawberries, and other allergens substances.
These IgE antibodies, once produced, bind to white blood cells and lead to the release of substances like histamine. This further causes constriction of bronchi in the lungs in allergic or asthmatic persons. Other signs and symptoms which can develop in these patients include running nose, skin itching, itchy eyes.
The severity of the reaction depends upon the body’s exposure to allergens which can be observed from mild reddening and itching of skin to problems in breathing (respiratory distress) to vomiting and diarrhea to conditions of shock.
Interpreting IgE results
IgE < 64.0o kUA/L
*Reference range may vary from lab to lab