Allergen Specific IgE Test
What is allergen-specific IgE testing?
An allergen-specific immunoglobulin E (IgE) test is a blood test that measures the levels of different IgE antibodies in a person's blood. Allergen-specific IgE tests are sometimes used to diagnose and better manage food allergies. They can also be helpful for environmental allergy diagnosis in some cases.
In some people who are prone to food allergies, the immune system mistakenly views specific foods as outside invaders and produces antibodies against them. The type of antibodies produced are IgE antibodies. These are different than the IgG antibodies which are important for fighting off bacteria and viruses. Allergen specific IgE testing can detect high levels of food-specific IgE to help figure out if an individual is allergic to a food. It is important to understand that there is a high rate of false positive testing with food-specific IgE testing, so large panels of food IgE testing are not recommended. In addition, this type of testing nor skin testing can help predict the severity of an allergic reaction.
Common allergens that can be detected through allergen-specific IgE testing include:
- Dust mites
- Certain foods (such as milk, egg, peanuts and others)
- Insect venom from bites or stings
Why your child may need an allergen-specific IgE test
Your child’s doctor may order an allergen-specific IgE test if your child has some or all the following symptoms of an allergy:
- Itchy or watery eyes
- Shortness of breath
- Stuffy or runny nose
An allergen-specific IgE blood test may be used in addition to or instead of skin testing. IgE blood tests are often used when children have a skin condition that may interfere with skin testing or cannot stop taking their antihistamines.
What to expect from an allergen-specific IgE test
A healthcare professional will use a small needle to collect blood from a vein in your child’s arm. If your child is an infant, the blood will be collected by pricking your child’s heel with a small needle.
Your child will feel a quick pinprick. The blood will be collected into a vial, then a small bandage will cover the site. The procedure takes only a few minutes.
How to prepare for an allergen-specific IgE test
Prepare your child for the test as you would for any blood draw. For children who get especially anxious around needles, a child-life specialist may be able to help distract your child while testing is performed. You will be able to stay with your child during this testing.
Talk to your child's healthcare professional about which allergy test is best for your child's specific symptoms and how to best prepare your child.
After allergen-specific IgE testing
Allergen-specific IgE blood tests are safe and there are minimal risks. After the test, your child may have a small bruise or mild soreness at the injection site for a few days. If discomfort is extreme or lasts longer, talk to your child's doctor.