Allergen-Specific IgE Blood Test

What Is the Allergen-Specific IgE Test and Why Is It Done?

An allergen-specific immunoglobulin E (IgE) blood test measures the levels of IgE in blood as one way of checking for certain allergies. These allergies may be a reaction to:

• food
• animal dander or insects
• pollen
• mold
• dust mites
• medicine
• latex (a stretchy kind of material)

Doctors might order allergen-specific IgE tests if kids have allergy symptoms after coming into contact with allergens (the things that can bring on allergies, like pollen). Allergy symptoms can include hives, trouble breathing, coughing, belly pain, vomiting, a stuffy nose, a scratchy throat, itchy eyes, or swelling of the face or throat.

What Is IgE?

IgE, short for immunoglobulin E, is a kind of protein called an antibody. The immune system makes antibodies to recognize and get rid of germs it thinks are harmful. But sometimes the immune system sees allergens as threats.

Top Things to Know

• The allergen-specific IgE blood test checks the levels of IgE in the blood for things that might lead to allergic reactions.
• The test helps doctors diagnose possible allergies.
• Kids might need to stop taking certain medicines before the blood test.
• Your doctor can explain what it means if allergen-specific IgE levels are high.

How Can I Help My Child Prepare for a Blood Test?

To help kids get ready for a blood test, find out if they should stop taking medicines before the test. Explain what to expect during the test. If your child is nervous about it, work together on ways to stay calm. Deep breathing or even imagining being in a place that makes your child feel safe and calm can help.

What Do Allergen-Specific IgE Test Results Mean?

Your doctor will explain what the results of the allergen-specific IgE test mean for your child. What’s “normal” varies based on things like age and gender.

Blood usually has small amounts of IgE antibodies, which are different depending on what allergens they react to. An allergen-specific IgE test can show what allergens the body is responding to.

If the level of an allergen-specific IgE is high, it means that the body is overreacting to that allergen. More testing may be needed to see if a person has an allergy to that allergen.

What Else Should I Know?

When doctors check for allergies, sometimes kids will have allergen-specific IgE tests and allergy skin tests. Allergy blood work used to be called RAST blood tests, but that’s an old brand name, and newer tests are used now. Along with allergen-specific IgE tests, kids may have a total IgE test so doctors can see how specific IgE levels compare to the total IgE level.

If you have questions about the allergen-specific IgE test or other allergy testing, talk to your doctor.