MEASUREMENT OF NATURAL-RUBBER LATEX ALLERGEN LEVELS IN MEDICAL GLOVESBY ALLERGEN-SPECIFIC IGE-ELISA INHIBITION, RAST INHIBITION, AND SKIN PRICK TEST

Exposure to natural rubber latex (NRL) medical gloves poses risks to p atients sensitized to NRL and to users of protective gloves. Previous studies have shown that extractable allergen levels of the gloves vary widely Since most of the available laboratory methods of NRL allergen measurement lack adequate validation, we wanted to evaluate the perfo rmance of a recently developed competitive IgE-ELISA-inhibition method in relation to the skin prick test (SPT) and RAST inhibition, as well as to extractable protein quantification and an immunochemical latex antigen assay (LEAP). Twenty samples of surgical (n=14) and examinatio n gloves (n=6), covering >90% of medical gloves marketed in Finland in 1994-5, were collected by the Finnish National Research and Developme nt Centre for Welfare and Health, coded, extracted, and analyzed by th e five methods. The IgE-ELISA inhibition correlated highly significant ly with SPT (r=0.94) and PAST inhibition (r=0.96). Likewise, ELISA inh ibition and RAST inhibition showed highly significant correlation (P=0 .96, P<0.0001 in all three instances). Protein quantification by a mod ified Lowry method also correlated highly significantly with SPT (r=0. 80), PAST inhibition (r=0.82), and ELISA inhibition (r=0.81, P<0.0001 in all three instances), Clearly weaker correlation, though statistica lly significant (r=0.48, P=0.03), was found between SPT and the LEAP a ssay An NRL standard preparation was assigned an arbitrary content of 100 000 allergen units (AU) per ml. In relation to this standard, the NRL allergen level was considered low (<10 AU/ml) in 11, moderate (10- 100 AU/ml) in two, and high (>100 AU/ml) in seven of the 20 glove bran ds analyzed. In conclusion, the results of a novel IgE-ELISA-inhibitio n method of measuring NRL allergen levels in medical gloves correlated highly significantly with those of SPT. The ELISA method was found to be sensitive, reproducible, technically easy inexpensive, and suitabl e for the analysis of large numbers of NRL products. The results of ex tensive market surveys in 1994 and 1995, communicated to the medical c ommunity in Finland, appear to have had a clear effect in moving glove purchasing policies toward the use of low-allergen gloves.