Allergen testing can be used to detect allergies. Allergen testing can be done in the allergy department, dermatology department or ear, nose and throat department of a hospital. It is a clinical aid that can be done in vivo, such as a skin test, or in vitro, such as a blood test, to observe the reaction of the body’s skin tissues or blood serum to allergens. This in turn helps you to determine whether you are allergic to these common allergens, such as dust mites, various pollens, foods, medications, chemicals, and so on. This laboratory test can identify the specific allergens that cause allergic reactions, assist in determining whether you are suffering from an allergic reaction disorder, and assist in determining the type of allergic reaction disorder. For blood tests there is generally no risk. In vivo tests such as skin tests may have adverse reactions. Localized reactions may be erythematous, windswept bumps that continue to grow in size. Local reactions usually subside within 24 hours. If allergic items are present, take care to avoid daily contact with allergenic items. If allergy occurs, prompt hospitalization is recommended.