Purpose of the test

The purpose of a total IgE test is to measure the sum of all kinds of IgE antibodies that are in the blood. The test is mainly used for diagnosis and treatment planning.

Diagnosis is the process of determining the cause of symptoms. Total IgE levels can be affected by many conditions, so total IgE testing by itself does not establish a diagnosis. However, a total IgE test may be helpful in the diagnostic process for specific health conditions that can cause abnormal total IgE levels including:

• Infections with parasites
• Allergic bronchopulmonary aspergillosis, which is an allergic reaction to a type of fungal infection in the lungs
• Certain kinds of immune disorders or cancers of the immune system

Infrequently, total IgE testing may be performed as part of allergy testing because many allergic reactions involve the production of IgE antibodies to normally harmless substances. However, total IgE testing cannot identify specific allergies or conclusively determine if a person has allergies at all. For this reason, it is not commonly used in allergy testing.

Treatment planning involves deciding what treatment may be appropriate for a patient. For people with asthma tied to allergies, a total IgE test may be used to determine whether certain types of treatment are likely to be beneficial.

What does the test measure?

The total IgE test measures the quantity of immunoglobulin E (IgE) in the blood. IgE is a type of antibody. Antibodies are proteins that the immune system produces to help defend against potential threats.

The immune system produces IgE antibodies for many specific substances. A total IgE test measures the sum of all these different IgE antibodies in the blood.

When should I get a total IgE test?

A total IgE test is usually only used in specific circumstances.

Your doctor may suggest a total IgE test if you have symptoms of an immune disorder, parasitic infection, or an allergic reaction from a fungal infection in your lungs. A total IgE test may be prescribed if you have asthma or if you have allergy symptoms like itchy or watery eyes, congestion, or sneezing.

Your doctor may also recommend total IgE testing if you have previously been diagnosed with asthma caused by allergies. In this situation, testing may help determine the right treatment for you and identify the right dosage of certain asthma medications.