title: Outcome of a second patch test reading of TRUE Tests® on D6/7.
abstract: Background. Two readings of patch test reactions are recommended. Objectives. To evaluate the outcome of a second patch test reading of TRUE Test® allergens on D6/7 in relation to negative or doubtful reactions on D3/4. Methods. This was a retrospective investigation of patch test data from January 1992 to October 2011 from consecutive eczema patients tested with the TRUE Test® panels. Results. In the period of nearly 20 years, a total of 9997 patients were tested. The total number of positive reactions to the 29 allergens was 6509; 4.4% were positive on D6/7 and negative on D3/4; and 9.1% were positive on D6/7 after a doubtful (?+) reaction on D3/4. Neomycin was the most frequent allergen giving delayed positive reactions (57%), followed by budesonide (42%) and hydrocortisone-17-butyrate (31%). Conclusion. A total of 4.4% of positive TRUE Test® reactions would be missed, and 9.1% might be missed, if only one reading was performed on D3/4. The results emphasize that many doubtful reactions at D3/4 may develop into positive reactions at a later reading. This may have important implications for evaluation of the clinical relevance of the test result.
authors.affiliation: Department of Dermatology and Allergy Centre, Odense University Hospital, University of Southern Denmark, Odense, Denmark.
authors.forename: Jakob Torp
authors.initials: JT
authors.lastname: Madsen
authors.forename: Klaus Ejner
authors.initials: KE
authors.lastname: Andersen
mesh_terms: D000305:Adrenal Cortex Hormones / Q000009:adverse effects; D000328:Adult; D000367:Age Factors; D000485:Allergens / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis*; D003951:Diagnostic Errors / Q000517:prevention & control; D005260:Female; D006801:Humans; D008297:Male; D009355:Neomycin / Q000009:adverse effects; D010328:Patch Tests / Q000379:methods*; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects; D012189:Retrospective Studies; D012737:Sex Factors; D013997:Time Factors
chemical_list: D000305:Adrenal Cortex Hormones; D000485:Allergens; D011310:Preservatives, Pharmaceutical; D009355:Neomycin