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Blood Test: Immunoglobulin E (IgE)

Reviewed by: Larissa Hirsch, MD
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What Is a Blood Test?

By taking and testing a small sample of a person’s blood, doctors can check for many kinds of diseases and conditions. Blood tests help doctors check how the body’s organs are working and see if medical treatments are helpful.

To help your child get ready for a blood test, find out if they need to fast (not eat or drink) or should stop taking medicines before the test. Explain what to expect during the test. If your child is anxious about it, work together on ways to stay calm.

What Is an Immunoglobulin E Test?

An immunoglobulin E (IgE) test measures the level of IgE, a type of antibody. Antibodies (also called immunoglobulins) are proteins the immune system makes to recognize and get rid of germs. The blood usually has small amounts of IgE antibodies. Higher amounts can be a sign that the body overreacts to allergens, which can lead to an allergic reaction.

IgE levels can also be high when the body is fighting an infection from a parasite and from some immune system conditions.

Why Are IgE Tests Done?

Doctors may order an IgE test if a child has signs of a possible allergy, immune system problem, or infection with a parasite.

What if I Have Questions?

If you have questions about the IgE test or what the test results mean, talk to your doctor.

Reviewed by: Larissa Hirsch, MD
Date reviewed: September 2021