Skip to content

    Allergies Health Center

    Font Size
    A
    A
    A

    Allergy Tests

    Results

    A skin or blood test can tell you what substance, or allergen, may trigger an allergic response.

    Skin tests

    Skin tests work by exposing a person to suspected allergens and seeing if a reaction occurs. The results of the skin tests are available immediately after testing is done.

    Allergy skin tests 1

    Normal (negative):

    No raised red areas (called wheals) are created by the allergen.

    Abnormal (positive):

    A wheal created by the allergen is at least 1/8 inch (3 mm) larger than the reaction to the negative control. The larger the wheal, the more certain it is that the person is allergic to that specific allergen.

    Blood tests

    Allergy blood tests look for substances in the blood called antibodies. Results of allergy blood tests are usually available in about 7 days.

    Allergy blood tests

    Normal (negative):

    The levels of immunoglobulin E (IgE), a type of antibody, are the same as in a person who does not have allergies.

    Abnormal (positive):

    The levels of immunoglobulin E (IgE) antibodies for a particular allergen or group of allergens are above the normal level.

    What Affects the Test

    Reasons you may not be able to have a skin test or why the results may not be helpful include:

    1 | 2 | 3 | 4 | 5 | 6 | 7

    WebMD Medical Reference from Healthwise

    Last Updated: March 12, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

    Today on WebMD

    man blowing nose
    Make these tweaks to your diet, home, and lifestyle.
    Allergy capsule
    Breathe easier with these products.
     
    cat on couch
    Live in harmony with your cat or dog.
    Woman sneezing with tissue in meadow
    Which ones affect you?
     

    blowing nose
    Article
    woman with sore throat
    Article
     
    lone star tick
    Slideshow
    Woman blowing nose
    Slideshow
     

    Send yourself a link to download the app.

    Loading ...

    Please wait...

    This feature is temporarily unavailable. Please try again later.

    Thanks!

    Now check your email account on your mobile phone to download your new app.

    cat lying on shelf
    Article
    Allergy prick test
    VIDEO
     
    Man sneezing into tissue
    Assessment
    Woman holding feather duster up to face, twitching
    Quiz