Spiking with recombinant allergens to improve allergen extracts: benefits and limitations for the use in routine diagnostics: Part 19 of the Series Molecular Allergology.

Essentially, allergen components offer three possibilities to improve in vitro IgE diagnostics: Allergen components can be used individually for IgE determination.Allergen components can be combined as a mix in one test.Individual allergen components can be specifically added to the extract. Option (a) is currently being used most extensively in practice, while (b) represents more of a theoretical possibility. The specific addition ("spiking") of allergen components to an allergy extract (c) has been performed in the past for the ImmunoCAP® tests for latex (09/2001), hazelnut (05/2006) and wasp venom (06/2012). Through this approach under-represented allergen components could be compensated and the analytical sensitivity of the test systems significantly increased. In combined use with molecular Singleplex tests, these modified tests allow for new diagnostic possibilities. Clear communication from the manufacturer regarding in which test and from what time point on, recombinant allergens were added - and where this was not done despite under-represented allergen components - is important for the interpretation of the test results in routine clinical practice.