Quality management in IgE-based allergy diagnostics

Assays for total and allergen-specific (s) IgE are essential serological tests in the diagnostic work-up of immediate type hypersensitivity reactions and atopic diseases. Technical performance characteristics and clinical utility of IgE tests have been published in international guidelines. In the USA and in Europe, IgE tests are mainly performed by accredited medical laboratories and in Germany they are also performed by allergists carrying an OIII-limited license. Both have to perform continuously internal and external quality control measures including proficiency trials twice a year (in Germany). Due to the hetero-geneity of the assay's core allergen reagents, complex extracts and more recently defined allergenic molecules, and heterologous assay calibration, the results of qualitative and quantitative sIgE tests from different diagnostic manufacturers can vary considerably. Proficiency trial results are subsequently grouped according to each assay type. Passing acceptance criteria depend on national rules and regarding quality management. Future challenges include a more valid quantification of sIgE which would allow true comparisons with the international units for total IgE, and the use of harmonized allergen reagents for the most important allergen sources, which have hampered inter-assay comparability in the past.