FITkit® as a tool in risk management
Why do we need the latex allergen measurement tests (FITkit, ASTM D7427) at all?
The history of natural rubber latex (NRL) as the prime source of glove material, with its excellent barrier and other properties, is well known. Furthermore, a review of literature reveals that NRL gloves, when compared with alternatives, tend to be stronger, more flexible and preferred by some clinicians. On a daily basis, many other latex products are utilised in healthcare and by consumers; however, NRL gloves have been under pressure for more than 20 years due to the risk of allergies. Improvements in glove manufacturing and more extensive use of synthetic gloves have led to a marked decrease in allergy cases in developed countries in Europe and North America. Notwithstanding this diminishing trend, the risk of allergy continues to be considered in every hospital’s risk management policy. In order to assess the source of potential sensitization (a glove for instance), we need a tool for assessment. Since the total protein (ASTM 5712) or antigenic protein (ASTM 6499) assays do not provide definitive data for the presence of allergenic proteins, the FITkit or ASTM D7427 are the only currently available methods to directly provide this information. Specific allergen measurement is considered the best option to assess potential risks of medical gloves (REF 1). A number of scientific reports reveal that rubber products fulfilling the requirements for total protein (< 50 µg/g) or antigenic protein (<10 µg/g) can still contain clearly significant concentrations of allergenic latex proteins (REF 2-6). Therefore, data on the allergen content of gloves should be made available, and gloves with high allergen content (sum quantity of four major allergens over 1.15 µg/g, (REF 7)) should not be recommended.
What is the difference between ASTM D7427 and FITkit?
ASTM D7427-16 is an ASTM standard, defining properties of a generic test that allows for the reliable measurement of clinically relevant latex allergens, Hev b 1, 3, 5 and 6.02, respectfully. ASTM has made available Industry Reference Materials and guides via D7427 standard text, allowing everyone interested to create their own assay. FITkit is a commercially available test that is compliant with ASTM D7427. FITkit is available as ready-to-use test reagents or a testing service.
Impact of FITkit data on the quality of risk management
FITkit test data helps to reliably differentiate gloves (or any other latex products) with proven low allergen content from others. Furthermore, available information about the allergen content of latex gloves raises the credibility of the producer’s or distributor’s statement about glove properties. Logically, it will significantly improve users’ ability to choose low allergen content gloves. This practice, on the other hand, will reduce the use of high allergen content gloves and, in turn, lead to a decrease in the exposure of people to latex allergens. There are available reports revealing whether gloves contain less than 0.15 µg/g (FITkit detection) of clinically relevant allergens, making it more than likely that they can be used safely. Furthermore, products that contain such small amounts of the studied natural rubber allergens are very likely suitable for a significant number of sensitized users, and the use of these gloves is not likely to create a risk in most persons unaware of their allergy (REF 8, 9).
How can one be sure that the use of high quality protective gloves poses a minimal but acceptable risk for latex sensitive users?
Available guidelines typically recommend choosing synthetic alternatives instead of NRL gloves for sensitised users. At the same time there has been a search by manufacturers and health authorities for a methodology that would allow for confirmation that synthetic products are free of NRL. The latex-free definition is becoming more complicated, as it is usually based only on a manufacturer’s announcement, not on reliable test results. Synthetic gloves are recommended as safer alternatives, because they, by definition, do not contain NRL proteins. A recent publication by M. Angeles Gonzalo Garijo, et al. (REF 10) on NRL contaminated nitrile gloves in healthcare shows that this is sometimes not true. In this respect, to fulfil a recommendation of being safer alternatives, synthetic gloves should be verifiably clean of NRL, i.e. undergo periodic control. Currently, FITkit or D7427 would be a suitable method to convincingly demonstrate the absence of the four major NRL allergens in gloves or other rubber products, when the need for such a statement emerges.
How gloves with proven low allergen content influence public safety?
Knowledge of the allergen content of available gloves will significantly improve users’ ability to choose low allergen content gloves. This practice, on the other hand, will reduce the use of high allergen content gloves and, in turn, lead to a decrease in the exposure of people to latex allergens. Eventually this development could have a marked public health impact by further reducing the incidence of new cases of latex allergy. Limitations in predictability of sensitization to NRL and resulting allergic reactions should not preclude attempts to overcome the problems associated with assessing potential exposure risks to products containing NRL allergens. Latex allergen measurement is one of the specific tools available for overcoming latex allergy concerns.
- Tomazic-Jezic, V. et al. Performance of Methods for the Measurement of Natural Rubber Latex (NRL) Proteins, Antigens and Allergens. J Allergy Clin Immunol 2004:113:S211
- Kostyal, D. et al. Latex as a significant source of Hevea brasiliensis allergen exposure. Ann Allergy 2009
- Yagami, A. et al. Hev b 6.02 is the most important allergen in HCW Sensitized Occupationally by NRL gloves. Allergology International 2009; 58:347-355
- Mabe, D.O. et al. Allergenicity of latex rubber products used in South African dental schools. S Afr Med J 2009; 672-674.
- Mok, K.L. Immunological Measurement of Four Major Allergens in Natural Rubber Latex Medical Gloves. 5th International Rubber Glove Conference 2010 paper
- Koh, D. et al. A study of natural rubber latex allergens in gloves used by healthcare workers in Singapore British Journal of Dermatology 2005 153, pp954–959
- Palosuo, T. et al. Latex allergy: the sum quantity of four major allergens shows the allergenic potential of medical gloves. Allergy 2007; 62:781-6.
- Turjanmaa, K, Kanto, M., Kautiainen, H., Reunala, T., Palosuo, T. Long-term outcome of 160 adult patients with natural rubber latex allergy. J Allergy Clin Immunol 2002; 110:S70-4.
- Glove study 2005. Finnish National Agency for Medicines, www.nam.ﬁ/english/publications.
- Gonzalo Garijo M. A. et al. Hypersensitivity reactions due to nitrile gloves, J Allergy Clin Immunol 2011