Comparison of allergen responses based on the TRUE Test and IQ Chamber system in Korean patients

Background A comparison between responses to allergens based on the TRUE Test® (TT) and IQ® Chamber (IQC) in Europeans has been previously reported, however, no such study has been performed in Asians. Objectives To compare allergen responses using the TT and IQC (using the Korean standard series) in order to gather more information regarding the positive response rates for each allergen and the clinical value of IQC. Materials & methods Suspected contact dermatitis patients were enrolled and tested with 18 allergens using the TT and IQC. Results The test was performed in 214 patients. Simultaneous positive results for both tests were recorded in 242 cases (positive concordance rate: 66.7%). IQC yielded more positive results. Allergens with a high positive concordance rate were nickel sulphate (82.1%), thimerosal (78.6%), and p -phenylenediamine (73.3%). IQC mostly showed similar or higher positive rates than TT, with high concordance. Conclusions We recommend the IQC method as a screening test in patients with suspected contact dermatitis. To compensate for possible false positive results, careful history taking and a different patch test should be performed when appropriate.