Comparison of reactivity to allergens using the TRUE Test and IQ chamber system.
ABSTRACT The reproducibility of the patch test is of great importance to its diagnostic utility. The objective of this study was to quantitatively and qualitatively compare the reproducibility of patch test reactions between the manufacturer-loaded TRUE Test (TT) panel and the investigator-loaded IQ Chamber (IQC) system using the European Standard Series (ESS) (Chemotechnique Diagnostics, Malmö, Sweden). Consecutive patients were simultaneously patch tested with 21 allergens using the TT and IQC system. The concordance and discordance of the 2 methods were analysed. Testing was performed in 207 patients (85 men and 122 women) who yielded 317 positive reactions, 188 with the IQ system and 129 with the TT. A total of 204 tests were positive with both methods, showing a positive concordance rate of 64.4%, with IQC producing more positive results. A high concordance rate of positive results was achieved for Cl+ Me- isothiazolinone (81.5%), nickel sulfate (79%), formaldehyde (76.9%), and paraphenylenediamine (PPD) (72.7%); a moderate concordance was noted for quaternium 15 (66.7%), potassium dichromate (64.3%), and fragrance mix (58.1%); and a low concordance was noted for cobalt chloride (27.6%) and Balsam of Peru (18.2%). The IQC and the TT are similar in finding allergy to allergens with high concordance. The IQC system has an advantage in detecting clinically relevant reactions to allergens that have a moderate and a low concordance.
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ABSTRACT: The concentration of nickel sulphate was determined in 9-16 mg test samples from commercially available patch test antigens. With two different manufacturers of 2.5% nickel sulphate in pet, the concentration range of 25 samples was 0.7 and 1.1% (+/- 2 SD) respectively, and with one manufacturer of 5.0% nickel sulphate in pet, the range was +/- 0.5%. In a normal patch test, the volume of patch test material applied with the Finn chamber technique should be 12-18 microliter (9-16 mg), but has been found to range between 9 and 50 microliter. Thus the amount of nickel applied in standard patch tests varies within at least 6-fold limits.Contact Dermatitis 12/1984; 11(5):285-7. · 2.93 Impact Factor
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ABSTRACT: The efficiency and reproducibility of patch tests remain controversial. Our purpose was to determine the efficiency and reproducibility of patch tests and to identify factors influencing these features. We double-tested 1285 patients concomitantly with 10 standard allergens by manually filled test chambers. Additional information was obtained from all patients with a standardized protocol. Patch test efficiency was good (> or = 0.94) with all 10 allergens. In contrast, nonreproducibility of patch tests was strongly allergen dependent, ranging from 0.2 for nickel sulfate to 0.6 for formaldehyde. The likelihood of nonreproducible allergic reactions increased when more than four positive reactions were seen at the same time, and with another positive reaction located in close proximity to an allergic reaction. Sex and age of patients, atopy, dermatitis at distant sites, sleeping habits, and the time of allergen exposure (24 or 48 hours) did not affect the rate of nonreproducible results. To increase patch test reproducibility, specific preparations of patch test allergens need to be improved. Furthermore, amplification effects by synchronous neighboring positive reactions should be excluded.Journal of the American Academy of Dermatology 10/1994; 31(4):584-91. · 4.91 Impact Factor
- Contact Dermatitis 06/1990; 22(5):288-9. · 2.93 Impact Factor