A new, standardized, ready-to-apply patch test, the TRUE Test, has been evaluated on 698 consecutive patients with suspected contact dermatitis. The patients were tested with 12 different allergens. Simultaneously, the same 12 allergens in pet. (Trolab) were applied symmetrically to the opposite side of the upper back using the conventional Finn Chamber technique. There were positive test reactions to all 12 allergens tested in the patient group. The concordance of positive reactions between the TRUE Test and the Finn Chamber test was 67%; 13% of all positive reactions were recorded only for the TRUE Test and 20% only for the Finn Chamber method. The frequency of questionable and irritant reactions was of the same low order of magnitude for both test methods; such reactions were recorded in around 2% of all test patches.