How do you test for food allergies?
- Oral challenge test. During this test, your allergist will give you or your child small amounts of the food suspected of causing the allergy. The food may be given in a capsule or with an injection. You’ll be closely watched to see if there is an allergic reaction. Your allergist will provide immediate treatment if there is a reaction.
- Elimination diet. This is used to find which specific food or foods is causing the allergy. You’ll start by eliminating all suspected foods from your child’s or your diet. You will then add the foods back to the diet one at a time, looking for an allergic reaction. An elimination diet can’t show whether your reaction is due to a food allergy or a food sensitivity. An elimination diet is not recommended for anyone at risk for a severe allergic reaction.
- Skin prick test. During this test, your allergist or other provider will place a small amount of the suspected food on the skin of your forearm or back. He or she will then prick the skin with a needle to allow a tiny amount of the food to get beneath the skin. If you get a red, itchy bump at the injection site, it usually means you are allergic to the food.
- Blood test. This test checks for substances called IgE antibodies in the blood. IgE antibodies are made in the immune system when you are exposed to an allergy-causing substance. During a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
How long until you receive results?
Typically your test results will be available within 3 to 7 days.
How often should you test for allergies?
Two years between allergy tests is reasonable – there are no limitations to the frequency of testing. We typically recommend retesting for symptomatic or therapeutic reasons.
Food Allergy Testing Vs Food Sensitivity Testing
The difference between a food allergy and sensitivity is the body’s response. When you have a food allergy, your immune system causes the reaction. If you have a food sensitivity or intolerance, the reaction is triggered by the digestive system.