[Present situation and problems in allergy testing in vitro]

The present situation and problems related to in vitro assays for measurement of specific immunoglobulin E(IgE) are described. A comparison of four commercially available assay kits(CAP, AlaSTAT, MAST and QAS) revealed that of the allergens studied, common ragweed, mugwort and fungus(aspergillus, candida and alternaria) showed low correlation coefficients. The precise reason for this discordance is not clear, however, we speculated that difference in the origin and extraction method of allergens may affect the correlation results. Random between-the-lot-difference was noted: the results for egg white and milk in QAS showed differences of two classes, although the total imprecision expressed in CV(%) was less than 12% when only a single lot was tested. These results suggest that the specific IgE assay may need an improvement in reagents(approval of standard materials and establishment of standard procedures for allergen extraction) and careful daily quality control by the user.