The Immunoglobulin E (IgE) Test: What to Expect

Allergies occur when the immune system reacts to a foreign substance from something eaten, touched, or inhaled into the lungs.

Over 50 million Americans have at least one allergy, and allergies are the sixth leading cause of chronic illness in the United States. Allergic conditions are also a common reason many people visit their healthcare providers for testing. In extreme cases, anaphylactic allergies can also be deadly.

One way to help diagnose an allergy is through a blood test that measures immunoglobin (IgE). IgE is an antibody that helps the body fight off foreign bodies, such as bacteria and viruses. An allergen-specific IgE blood test can measure the levels of different IgE antibodies. If they are too high or too low, it may suggest that the person has a more serious health condition.

This article will explain who should have an IgE test, what to expect, IgE levels, and treatment for high IgE results.

Who Should Be Tested?

An allergen-specific IgE test may be done to look for some kinds of allergies, which can include:

• Types of food
• Pollen
• Latex
• Mold
• Some types of medicine
• Animal dander
• Pollen
• Dust mites

An IgE test can also help monitor a person with a known allergic condition, such as:

• Anaphylaxis: A life-threatening allergic response
• Allergic conjunctivitis: Eye allergies
• Asthma
• Allergic rhinitis: Hay fever
• Chronic rhinosinusitis: Inflammation of the nasal passages and sinus cavities

Your healthcare provider may also recommend an IgE blood test if you're experiencing allergy symptoms, such as:

• Sneezing
• Coughing
• Wheezing
  
• Stuffy or runny nose
• Itchy, watery eyes
• Hives (itchy, raised red patches on the skin)
• Diarrhea or vomiting
• Shortness of breath

Allergy blood tests are also available for those who cannot tolerate allergy skin testing. This requires placing an allergen directly on the skin. A blood test may be preferred if an individual is at high risk of developing a severe reaction to an allergy skin test or for young children who may be too uncomfortable having a skin test.

What to Expect

Types of IgE blood tests include:

• A total IgE test: A measurement of the total amount of IgE antibodies in your blood.
• A specific IgE test: A measurement of how much IgE your body makes in response to a particular allergen.

The blood test usually takes less than a few minutes and requires a quick needlestick prick. First, a healthcare provider will insert a small needle into one of the veins in your arm. After insertion, a small amount of blood will be collected into a test tube or vial.

There is no preparation for an IgE blood test. After the blood collection, your healthcare provider will apply pressure to the area for a few minutes and apply a Band-Aid. You may have a small bruise for a few days at the site.

Results

Everyone has some IgE in their blood. If IgE test results suggest you have an allergy, your healthcare provider may refer you to an allergist or immunologist who can help with a treatment plan.

High IgE

A total IgE test result that is high means that you could have some kind of allergy. A high specific IgE test result means that you may be allergic to the allergen tested.

But both results don't show what you're allergic to or how severe your allergy may be. Your healthcare provider may recommend more testing.

Normal IgE

Everyone has some IgE in their blood. Different allergy blood test brands can vary in how they test for IgE. However, a normal result typically means that the test did not indicate an allergy.

Low IgE

Low serum IgE is associated with:

• Chronic fatigue
• Asthma
• A higher likelihood of autoimmune and oncological diseases
• Chronic sinusitis, or inflamed sinuses
• Otitis media, or fluid in the ear

Treatment

Your treatment plan will depend on what you are allergic to and how serious your symptoms are.

Your allergy specialist may recommend additional testing to help determine each allergen that may be causing your allergies, such as:

• A skin prick test (SPT)
• An intradermal test (IDT)

These tests require placing a small number of substances that may be causing allergies on or just beneath the skin's dermis, most often on the back or arm.

One of the most effective treatment plans for allergies involves avoiding the allergen altogether. Home remedies for mild allergies may include:

• Using an air filter or dehumidifier
• Nasal irrigation
• Vitamin D
• Acupuncture
• Butterbur
• Stinging nettle tea

Prescription and over-the-counter (OTC) medications may help with allergy systems, such as:

• Antihistamines: Block histamines to reduce allergy symptoms
• Decongestants: Help relieve congestion
• An asthma inhaler: A hand-held device containing a medication called a bronchodilator that delivers medicine to your lungs

Talk to your healthcare provider first if you want to try medications for allergies.

Summary

An allergen-specific IgE blood test can measure the levels of different IgE antibodies. If they are too high or too low, it may suggest that the person has a more serious health condition.

A Word From Verywell

Allergies can range from mildly annoying to completely miserable or even dangerous. Fortunately, allergy testing is available to you that can help determine the source of your allergies so you can make lifestyle changes to help you avoid those allergens.

If avoiding allergens completely is not possible, some helpful home remedies or medications may help ease your symptoms. However, talk to your healthcare provider before taking any medications. Your healthcare provider can help determine the best care plan for you and may recommend you to an allergy specialist for additional testing and treatment.