The TRUE Test standard panel consists of two tape strips, panel 1 with 11 allergen patches and a negative control and panel 2, with 12 allergen patches. TRUE test panel 1 and 2 contain 23 of the most frequent contact allergens.With these 23 allergens, it is possible to detect about 60-70% of contact allergic reactions. Thus, there is a need for expanding the number of allergens included in TRUE Test in order to detect more contact allergic reactions. Therefore goldnatriumthiosulphate, methyldibromoglutharonitrile and parthenolide are developed for inclusion in a third TRUE Test panel. This study is a dose-response study using 3 dilution series to detect the optimum concentration of the 3 allergens. A phase-III study will be performed afterwards to establish the efficacy and safety of the three allergens.