Allergy to natural rubber latex (NRL) proteins is recognized as an occupational problem among subjects using protective gloves. A major group at risk of immediate hypersensitivity reactions to NRL consists of operating room nurses and surgeons of whom 5% to 11% have been shown to be allergic to latex.1 Importantly, NRL gloves are also the major contributor to latex aeroallergen levels in operating rooms.2 Several studies have documented considerable differences between the allergen content of latex gloves made by different manufacturers, and even between gloves of different batches from a single
manufacturer.3-5 Other manufactured NRL products, such as household gloves, catheters, condoms, baby pacifiers and toy balloons may also contain allergenic proteins.1
An initiative to analyze allergen contents of latex gloves marketed in Finland and internationally was taken in 1994 by the Finnish National Research and Development Centre for Welfare and Health. First, coded extracts of 20 gloves, covering over 90% of the 1994 market, were examined using three different methods, i.e., skin prick test, IgE-ELISA-inhibition and RAST-inhibition. Highly significant correlations (r = 0.94-0.96) emerged between the results of the two laboratory methods (RAST-inhibition and ELISA-inhibition) and the results of prick tests, the "gold standard" for diagnosing latex allergy.5 Based on these results, it was agreed that subsequent surveys would use the IgE-ELISA-inhibition method only.
In 1995, The Medical Devices Centre of the National Agency for Medicines, Finland, provided 65 glove samples from 15 different importers for allergen analysis, again covering more than 90% of the medical glove market. The results of these studies were communicated to the medical community both in Finland and internationally.6
To continue monitoring the levels of NRL allergens in marketed natural rubber products and to see whether the published information would influence glove purchasing and glove-usage policies in Finland, a third market survey was carried out in 1997. A full report of this study, including materials and methodology, can be found by visiting the web site http://home.netcom.com/~nam1/NAM.html.
RESULTS
Fifty-six of the 69 glove samples were found to represent different glove types or batches. Altogether 30 of theses 56 glove samples (53.6%) had low allergen content (< 10 AU/ml), 18 samples (32.1%) had moderate (10 - 100 AU/ml) and 8 samples (14.3%) had high allergen content (> 100 AU/ml).
COMMENTS
Various research efforts have been undertaken to quantify the allergen content3-4 of gloves with the ultimate goal of decreasing sensitization by eliminating the use of high allergen gloves and eventually withdrawing them from the market. Availability of specific methods for measuring allergen levels in manufactured rubber products has been scant. Total protein measurement has shown to correlate relatively well with true allergen contents (measured by e.g. skin prick test) of manufactured products5-7 although such methods also measure non-allergenic proteins. The regulatory health authority in the USA, The Food and Drug Administration (FDA), and the European Committee for Standardization (CEN) have, nevertheless, introduced the measurement of extractable total protein as a simple option for glove manufacturers to monitor their product and to provide information for glove users. Allergen-specific assays provide much more reliable information but, unfortunately, most methods used for this purpose lack adequate validation and are not easily available. The National Agency for Medicines has taken the advantage of using a recently developed and validated method, a latex-specific IgE-ELISA-inhibition,5 to monitor in a nation-wide scale the allergen content of latex gloves sold and used in Finland.
Three successive market surveys, each covering over 90% of the locally marketed medical gloves, were carried out in 1994-1997. During this period, the proportion of high-allergen gloves versus all medical gloves offered for sale decreased from 30% to 14%, that of moderate-allergen gloves increased (from 15% to 32%) while low-allergen gloves remained more than half of the market (55-63-54%). Several high-allergen gloves disappeared from the market6 and the mean allergen content in the remaining high-allergen gloves available has decreased (from 569 AU/ml to 338 AU/ml). In 1997, approximately one half of the available low-allergen gloves had very low levels, i.e. below 1 AU/ml, while only 3 of 11 low-allergen gloves in 1994 fell into this category. Obviously, many factors could have influenced this development but it is tempting to assume that awareness of the problem and the availability of low-allergen products, identified in the surveys, have played an important role.
In summary, the authors arrive at the same conclusion presented earlier,6 that this type of repeated nationwide market analyses, preferably arranged by regulatory health authorities, and effective communication of the results, enable appropriate low-allergen glove selection. The goal is to reduce the incidence of latex allergy.
REFERENCES
- Turjanmaa K, Alenius H, Mäkinen-Kiljunen S, Reunala T, Palosuo T. Natural rubber latex allergy (review). Allergy 1996; 51;593-602.
- Heilman DK, Jones RT, Swanson MC, Yunginger JW. A prospective, controlled study showing that rubber gloves are the major contributor to latex aeroallergen levels in the operating room. J Allergy Clin Immunol 1996; 98;325-30.
- Turjanmaa K, Laurila K, Mäkinen-Kiljunen S, Reunala T. Rubber contact urticaria. Allergic properties of 19 brands of latex gloves. Contact Dermatitis 1988; 19;362-7.
- Yunginger J, Jones R, Fransway A, Kelso J, Warner M, Hunt L, Reed C. Extractable latex allergens and proteins in disposable medical gloves and other rubber products. J Allergy Clin Immunol 1994; 93;836.
- Palosuo T, Mäkinen-Kiljunen S, Alenius H, Reunala T, Yip Esah, Turjanmaa K. Measurement of natural rubber latex allergen levels in medical gloves by allergen-specific IgE-ELISA-inhibition, RAST-inhibition, and skin prick test. Allergy 1998;53:59-67.
- Palosuo T, Turjanmaa K, Reunala T, Mäkinen-Kiljunen S, Alenius H. Allergen content of latex gloves used in 1994-1996 in health care in Finland. Results of renewed market survey in 1995. Publications of the National Agency for Medicines 1996;2:1-7.
- Yip Esah, Turjanmaa K, Ng KP, Mok L. Allergic responses and levels of extractable proteins in NR latex gloves and dry rubber products. J Nat Rub Res 1994;9:79-86. This study was carried out by Palosuo, Turjanmaa and Reinikka-Railo and was published by the National Agency for Medicines (NAM) in Finland. Reproduced here with permission.
