atex Medical Gloves: Time for a Reappraisal
Many hospitals have implemented policies to restrict or ban the use of devices made of natural rubber latex (NRL) in healthcare as precautionary measures against the perceived risk of NRL allergy. Changes in glove technology, progress in measuring the specific allergenic potential of gloves and a dramatic decrease in the prevalence of NRL allergies after interventions and education prompted us to revisit the basis for justifiable glove selection policies. The published Anglophone literature from 1990 to 2010 was reviewed for original articles and reviews dealing with the barrier and performance properties of NRL and synthetic gloves and the role of glove powder. The review shows that NRL medical gloves, when compared with synthetic gloves, tend to be stronger, more flexible and better accepted by clinicians. The introduction of powder-free gloves has been associated with reductions in protein content and associated allergies. Recently, new methods to quantify clinically relevant NRL allergens have enabled the identification of gloves with low allergenic potential. The use of low-protein, low-allergenic, powder-free gloves is associated with a significant decrease in the prevalence of type I allergic reactions to NRL among healthcare workers. Given the excellent barrier properties and operating characteristics, dramatically reduced incidences of allergic reactions, availability of specific tests for selection of low-allergen gloves, competitive costs and low environmental impact, the use of NRL gloves within the hospital environment warrants reappraisal.
In recent years, many hospitals and health care settings around the world have decided to restrict the use or totally ban all natural rubber latex (NRL) devices as precautionary measures to NRL allergy threats. As is widely acknowledged, type I or IgE-mediated NRL allergy has, for several years, been one of the most significant occupational health problems [for reviews, see [1,2,3]]. However, it is now also acknowledged that new cases of NRL allergy have reduced significantly and sometimes virtually disappeared in countries and hospital regions where health authorities have required the use of low-allergen/low-protein, non-powdered protective medical gloves. Thus, policies which ban the use of NRL devices may be an overreaction that can lead to unexpected compromises in the primary purpose of using protective gloves, that is, providing a competent barrier to protect against infections for both healthcare professionals and the patients [4,5]. These controversies prompted us to revisit the basis for justifiable glove selection policies.
As is well known, NRL has been used as a material for the production of gloves for almost a century. Throughout the 1990s there were increasing concerns about transmittable diseases, particularly HIV infection and hepatitis, which resulted in a dramatic increase in the use of NRL gloves. Escalating glove use in the 1990s was associated with the rise in reports of allergic reactions to NRL gloves among healthcare workers [1,6,7,8,9,10]. The increased demand for gloves led to an upsurge in glove production, especially in Malaysia. Between 1987 and 1989 the Malaysian Rubber Development Board received over 400 applications to form glove companies where previously only 25 existed . Early on in the history of NRL allergy, some authors [12,13] suggested that the increased production in response to the sudden upsurge for latex gloves often led to inadequate leaching to reduce protein levels.
The healthcare community requires medical gloves, both for examination and surgery, in order to provide a barrier that prevents transmission of micro-organisms to and from patients . Many factors are involved in the choice of materials for the production of medical gloves, which relate to both the protective effect as well as ease and comfort of use [14,15]. For a large number of healthcare practitioners, NRL continues to be the glove material of choice [15,16].
The negative aspect of NRL glove use, linked to the allergy problems, has gained substantial media coverage, in addition to the publication of a significant number of scientific papers. In reaction to the media and scientific coverage, and to rising compensation claims, many hospitals around the world have implemented new latex allergy and glove policies, resulting in the substitution of NRL gloves with synthetic gloves in certain areas, on specific patients or by sensitized staff. More recently, a number of high profile hospitals, exemplified by Johns Hopkins Hospital in Baltimore, Md., USA, and the Cleveland Clinic’s network of nine hospitals in Cleveland, Ohio, USA, have gone ‘latex free’ . As a result, a small but increasing number of medical practitioners only have access to gloves made from synthetic materials. Such policies require full consideration of all of the factors involved, including also glove functionality as well as costs incurred, both directly and indirectly on the environment.
Following recognition of the problem of NRL sensitivity in the late 1980s and early 1990s, many changes were made in the production processes for NRL gloves and in the implementation of latex-sensitivity protocols in hospitals. In recent years, these changes have resulted in a significant reduction in the prevalence rates of allergic reactions to NRL. Experience from the Mayo Clinic, Rochester, Minn., USA  and Finland  showed that the change by an institute or hospital district specifically to low-allergen gloves or to gloves with undetectable allergen contents, led to a decrease in the incidence of new cases of occupational allergy. In Germany, Allmers et al.  showed that a combination of educating physicians and administrators, together with regulations requiring that healthcare facilities only purchase low-protein, powder-free NRL gloves, can even lead to prevention of sensitization.
This review compares the key properties of gloves made of NRL and synthetic source materials and examines glove barrier and functional characteristics, recent changes in glove technology, developments in NRL allergen measurement methodology as well as priority given by clinicians and other health care workers. The Anglophone literature limited largely to the period from 1990 to 2010 was surveyed for original research reports and review articles addressing also specifically the evidence for the consequent reductions in risk of allergic reactions and changes in the epidemiology of NRL allergies.
Glove Source Materials
Many plants produce liquid latex, but the natural material, NRL, used in rubber manufacture is almost exclusively obtained from the Hevea brasiliensis tree. It contains the rubber polymer, cis-poly-isoprene, as well as varying amounts of a large number of different proteins [20,21,22]. Various chemicals, such as accelerators, activators, anti-oxidants and vulcanizing agents, are used in the manufacture of medical gloves [; for review, see ] but a large proportion of these chemicals are then leached out in the further stages of production, through processes such as ‘wet-gel leaching’. These leaching processes also remove the majority of the water-soluble proteins found in NRL .
The raw materials for synthetic glove manufacture include vinyl (polyvinyl chloride), nitrile (acetonitrile butadiene), neoprene, polyisoprene, polychloroprene, polyurethane and polyethylene, which are generally derived from oil chemistry. Nitrile is very similar in its polymer chemical structure to NRL and, in this respect, may be considered as synthetic latex.
Deproteinised latex, being composed of enzyme-treated NRL, has also been used as the source material for nitrile gloves. We are not aware of published reports in which gloves made of deproteinised NRL have been compared with conventional NRL gloves, especially with respect to their allergenic properties, although there are reports that NRL-allergic patients can tolerate condoms made from this material .
Recently, liquid latex from a North American and Mexican desert shrub, Parthenium argentatum, commonly known as Guayule, has been introduced as