Nurse Checking Girl

Allergy Testing

 

Skin prick tests

  • This is the most common type of allergy testing that patients receive.

  • There are no needles involved in this type of testing.

  • Skin prick testing involves lightly touching a small plastic stick to your skin. Each stick has a tiny amount of liquid on the tip (which contains an allergen) that enters the top layer of your skin after it’s pricked.

  • If you have an allergy to the allergen, the area where the stick pricked your skin will become red with a small itchy bump. This takes about 10 – 15 minutes. 

  • If you do not have an allergy to the allergen, the skin will not react.

Intradermal skin tests

  • This type of testing is used for vaccine allergies and stinging insect allergies.

  • Intradermal skin testing does involve needles, but we do our best to perform the testing as quickly as possible.

  • Not everyone who is referred for a vaccine or stinging insect allergy will need intradermal skin testing. 

  • These tests also need to be ordered in, which is why the testing is not performed at the first appointment, and you will be put on a list to return for the testing if it is needed.

Allergy blood tests (specific IgE testing)

  • This type of test will sometimes be ordered for certain patients with a suspected food allergy if skin testing alone is not enough to determine whether a food allergy exists.

  • If this test is needed, a requisition will be provided and you will need to get the test done at a lab.

  • Like all blood tests, a small needle will be used to draw blood. A topical anesthetic cream/patch can be applied beforehand to minimize pain.

  • Note: this is different from IgG "food sensitivity testing" that can be performed without a physician's request.

Frequently Asked Questions

Will allergy testing be done at my appointment?

  • If your referral is for possible environmental allergies or asthma, you will likely need allergy testing.

  • If your referral is for a possible food allergy, you may or may not need allergy testing depending on the nature of your reaction.

  • If your referral is for an allergy to a medication (i.e. penicillin), vaccine, or insect sting (i.e. bee/wasp), the first appointment will be a consultation only, and we will book you back for another appointment if you need allergy testing.

  • If you have a strong preference for allergy testing to something specific, please bring it up during your appointment so we can discuss if it is necessary.

Do I need to bring anything for allergy testing?

  • Typically, no.

  • However, if your referral is for a possible food allergy, you do need to bring in a small piece of the food only IF the food is a fruit/vegetable, contains a mix of ingredients, or is an unusual food. If you are unsure whether you need to bring in food, call our clinic and we will inform you.

Can allergy tests be wrong?

  • Yes. Allergy tests are very helpful tools in determining if you have an allergy or not, but unfortunately they are not perfect and sometimes can be wrong. (Researchers are working on this, but we are not quite there yet).

  • False negative testing (having a negative allergy test when you are actually allergic) is rare, but can happen.

  • False positives testing (having a positive allergy test when you are not actually allergic) is more common than false negative testing, especially with food allergy testing. For this reason, allergy testing to foods that you have never had an allergic reaction to is generally not helpful and discouraged.

  • All allergy test results must be interpreted by your allergist for them to be valid.

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Disclaimer: This website is intended for informational purposes only. It is not meant to provide medical advice and should not be treated as such. For personal medical questions related to allergies, please speak directly with your physician. If you require emergency medical attention, please go to your nearest emergency room or call 911.

©2018 by Dr. Willa Liao, Kingston Pediatric Allergy