Allergy Testing
Allergy Blood Test
An allergy blood test measures the amount of allergen-specific IgE antibodies in the blood. It screens for at least ten of the most common allergy triggers, including trees, grasses, weeds, molds, pet dander, dust, and food-related allergens. Results are typically returned within a few days.
A blood test is the preferred option when a patient is taking medications that could interfere with skin test results — such as steroids, antidepressants, or antihistamines — or when a patient has a severe skin condition, unstable heart condition, or poorly controlled asthma. It is also easier to perform on young children. The two types of allergy blood tests are the enzyme-linked immunosorbent assay (ELISA or EIA) and the radioallergosorbent test (RAST).
About 50 to 60 percent of allergy blood tests may show a false-positive result, meaning the test shows a positive reaction even when no true allergy exists. The allergist will consider test results alongside the patient's symptoms and medical history before making a diagnosis.
Allergy Skin Test
Skin testing is the most commonly preferred method of allergy testing. A concentrated liquid form of each allergen is placed on the back and a lancet is used to lightly prick the outer layer of skin to allow the allergen to enter. After 15 minutes, the allergist reads the results. The test is not painful and has been compared to a mosquito bite. It can detect allergies to pollen, mold, dust mites, animal dander, and food.
If a reaction occurs, a small red, itchy bump will appear at the site of that allergen. Results are available before leaving the allergist's office. Risks are very low, though tests must be performed at an allergist's office in the rare case of a severe reaction. Certain medications may need to be stopped before the test.
Food Challenge Test
A food challenge test is another method used to confirm or rule out a food allergy. This test is also conducted at the allergist's office to ensure patient safety.
Inhalant Allergy Test
An inhalant allergy test is used to identify sensitivities to airborne allergens such as pollen, mold, dust mites, and pet dander that are inhaled through the respiratory system.
Insect Allergy Test
An insect allergy test is used to determine whether a patient is allergic to insect stings. This is especially important for patients who may be at risk for a severe or life-threatening reaction to insect venom.
Allergy Testing FAQ
What Is Allergy Testing?
Allergy testing has one goal: to identify the cause of allergic reactions so that symptoms can be managed and relief can be found. There are five types of allergy tests available: a blood test, a skin test, a food challenge test, an inhalant allergy test, and an insect allergy test. A physician may also review a patient's medical history for additional indicators. The right test depends on the type of allergy suspected and the patient's individual health situation.
How does an allergist use test results?
Once allergy testing is complete, the allergist reviews the results along with the patient's symptoms and medical history to reach a proper diagnosis. From there, the allergist and patient can work together to create an allergy action plan and determine the most appropriate course of treatment.