Allergic diseases, such as hay fever, asthma and food allergies, often warrant finding out what is triggering the allergy to guide treatment. Most allergies result in the production of immunoglobulin E (IgE) antibodies that are specific to that allergen, which can be detected with in vitro tests or skin testing. A new clinical report from the American Academy of Pediatrics (AAP), "Allergy Testing in Childhood: Using Allergen-Specific IgE Tests," in the January 2012 Pediatrics (published online Dec. 26), offers guidance for clinicians in using in vitro allergen-specific IgE testing. The report gives guidance to aid pediatricians in selecting the appropriate tests and interpreting the results in the context of a patient history and clinical presentation.