Results of patch testing with a special series of rubber allergens

The purpose of this study was to examine the results of patch testing with the rubber components on a standard screening tray and compare them with the results of testing with a special series of 27 rubber components (rubber tray). 1670 patients were patch tested with the screening tray and 317 of these were also tested with the rubber tray. 16% of those tested with the rubber tray had a positive response to at least 1 of the rubber allergens on the screening tray and 22% had a positive response to at least 1 of the allergens on the rubber tray. The most common positive response to the rubber tray allergens was to tetramethylthiuram monosulfide. There were no responses to 3 of the components on the rubber tray and there was only 1 positive response to a further 4 components. The diagnostic test characteristics of the rubber components on the screening tray were examined using the rubber tray as the gold standard. The sensitivity of the screening tray was 94%, specificity 51%, positive predictive value 87% and negative predictive value 71%. Of the 317 tested, 11% were found to have a positive to a substance on the rubber tray that was not evident from the results of the screening tray.