IgE Food Screen

Most tests for allergy are laboratory tests for allergic sensitisation or the presence of allergen-specific IgE. An individual who experiences symptoms when exposed to an allergen will usually have measurable IgE which specifically recognises that allergen. Testing allergen-specific IgE has fundamental importance for the diagnosis of allergic disorders.

Skin testing is the in vivo equivalent to allergen-specific IgE testing and has advantages, such as providing immediate results and being less expensive. However, it carries the risk of allergic reaction (including anaphylaxis), and results may be affected by antihistamines, dermographism and a narrower range of allergens being available, when compared to laboratory tests.

Regardless of the method used, the demonstration of sensitisation is not sufficient to diagnose allergy. Some sensitised individuals remain symptom-free after exposure and others, who react to an allergen, may not have any detectable allergen- specific IgE in their blood. Therefore, the results of allergy testing must be interpreted in the context of the patient’s clinical history; an allergy diagnosis cannot be made solely on the results of laboratory or skin testing.