Component-resolved diagnostics in the clinical and laboratory investigation of allergy

The diagnosis and management of allergy is complex; the clinical symptoms associated with allergic reactions span a broad spectrum of severity, from mild hay fever-type symptoms through to life-threatening anaphylaxis. Obtaining an allergy-focused clinical history is therefore vital for identifying possible allergic triggers and directing testing. However, this focus could be changing as scientific and technological advances have paved the way for developments within in vitro testing for allergy. With knowledge of allergens at the molecular level expanding, there are now the facilities to characterize the sensitization profiles of allergy sufferers and determine the specific molecules (or components) against which the allergen-inducing immunoglobulin type E proteins have been produced. This technology is termed component-resolved diagnostics. We know that accurate identification of immunoglobulin type E specificity, the source of the causative allergen, and knowledge of potential allergic cross-reactivities are required for optimal clinical management of allergy patients. These factors can make allergy a diagnostic challenge outside of a specialist centre, and contribute to the difficulties associated with requesting and interpreting allergy tests. The incorporation of component-resolved diagnostics into current practice has provided a platform for patient-tailored risk stratification and improved the application of allergen-specific immunotherapy, revolutionizing specialist management of these patients. This review discusses the roles of each type of testing in allergy management and predictions for future pathways.