Peanut Allergy Testing should be performed and evaluated by an allergist on anyone with a suspected peanut allergy. Possible tests include blood tests and skin tests. Skin testing might provide useful information, but must be done carefully as they is riskier than blood testing in severely allergic individuals.
Peanut allergy testing involves testing to determine if a substance (peanuts), or allergen, will trigger an allergic response in a person. Skin tests are usually performed since they are quick, reliable, and generally less expensive than blood tests, but both types of tests are used.
Peanut Allergy Testing: Skin Tests
Peanut allergy testing starts through putting by a small amount of a suspected allergen (peanuts) on or under the skin to see if a reaction develops. There are three types of skin tests:
* Skin prick test. This test is performed by putting a drop of a solution containing peanuts on the skin, where a series of scratches or needle pricks allows the solution to penetrate the skin. If red, raised itchy area (called a wheal) develops, it usually demonstrates that the patient is allergic to peanuts. A skin reaction constitutes a positive reaction.
* Intradermal test. This test is conducted by injecting a some of the peanut solution into the skin. An intradermal allergy test usually is performed when the peanut solution does not create a reaction in the skin prick test, but is still suspected as an allergen for that individual. The intradermal test is more sensitive than the skin prick test. However, it is more often positive in individuals who have no symptoms to peanuts.
* Skin patch test. A skin patch test involves attaching a pad with the peanut solution on the skin for 24 to 72 hours. This test is used to detect a skin allergy called contact dermatitis.
Peanut allergy testing using blood tests looks for peanut antibodies in the blood. Blood tests are not as sensitive as skin tests but they can be used in cases where people cannot withstand skin tests.
The most frequent type of blood test performed is the enzyme-linked immunosorbent assay (ELISA, EIA). It measures the blood level of an antibody (called immunoglobulin E, or IgE) that the body may produce in reaction to peanuts. IgE levels are usually higher in those who have peanut allergies.
Other lab tests, for example radioallergosorbent testing (RAST) or an immunoassay capture test (ImmunoCAP, UniCAP, or Pharmacia CAP), can be performed to elicit additional information.
Your allergy test results may indicate that allergy treatment is an option that can help you.