Allergy Tests

What To Think About

• You may not need allergy testing if you have mild allergies that are easily controlled with medicine or lifestyle changes.
• Skin tests:
  • Are the easiest and least expensive method for identifying allergies in most people.
  • Are more reliable than blood tests for identifying common inhaled (airborne) allergies, such as pollens, dust, mould, and pet dander.
  • Cannot tell whether a person is reacting to a certain food. Further testing (such as an elimination diet) may be needed to identify this.
  • Can be unpleasant for children and their parents.
  • May take as long as 3 to 4 hours.
• Allergy blood tests:
  • Are less sensitive than skin tests. Therefore, it is possible for people to have a positive reaction to a skin test but have a negative reaction to a blood test.
  • Are not affected by antihistamines or tricyclic antidepressants, so people do not need to stop taking these medicines while being tested.
  • May be a good choice if you have very sensitive skin or a skin problem, such as eczema, that would make it hard to see whether you have a reaction to a skin test.
  • Will not cause an allergic reaction. They may be used if you have had a serious allergic reaction in the past.
  • Cost more than skin tests.
• You may need to be tested for a latex allergy before having a major surgery if you have had frequent exposure to latex. Allergy blood tests are used for this. If you have a latex allergy, latex products should not be used during your surgery or recovery.
• Other blood tests, such as fluoro-allergosorbent testing (FAST), multiple antigen simultaneous testing (MAST), and radioallergosorbent testing (RAST), are sometimes used to check for allergens.

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Author:	Debby Golonka, MPH Ralph Poore	Last Updated: September 27, 2007
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Harold S. Nelson, MD - Allergy and Immunology Donald Sproule, MD, CM, CCFP, FCFP - Family Medicine
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