||January 1, 2007
Immediate allergic reactions to natural rubber latex (NRL) proteins continue to be an important medical and occupational health problem. Attempts at minimizing protein and allergen concentration in NRL gloves to prevent sensitization and the development clinical allergy to NRL are acknowledged as a goal of mutual interest for rubber manufacturers and regulatory health authorities. Total protein determination has been widely used for the indirect estimation of allergen content in NRL products but consensus exists today that allergen-specific assays that are specific, of high sensitivity and reproducibility and can be properly standardized, would provide much more reliable information. We quantified four NRL allergens (Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02) in 208 glove brands by a capture enzyme immunoassay (FITKit®). The results were compared with those from a skin prick test-validated human IgE-based ELISA-inhibition method that has been considered as the “golden standard” for demonstration of allergenicity of rubber products. A high overall correlation ( r=0.87, 95% CI 0.83 to 0.90) emerged between the sum values of the four allergens(µg/g glove) and IgE-ELISA inhibition. The sum, when set at 0.15 µg/g discriminated “low allergenic” (< 10 AU/ml) from “moderate to high allergenic” (>10 AU/ml) gloves at a sensitivity of 0.93 (95% CI 0.85 to 0.98) and specificity of 0.90 (95% CI 0.83 to 0.94). In conclusion, the allergenic potential of medical gloves could be assessed with remarkably high specificity and sensitivity. For the four allergen sum test we set up a cut-off level (0.15 µg/g) below which virtually all gloves can be considered as low allergenic. Although it is still not possible to make claims of safety, the specific allergen tests will be a very useful practical guide to personnel responsible for glove purchasing in hospitals and health care centers and also to conventional glove users to support their glove selection policies.