Significance and Use
IgE-mediated allergic reactions to protein allergens in natural rubber latex derived from the Hevea brasiliensis tree emerged in the 1990s as a concern with occasional allergic manifestations. Symptoms encompassing hives, uriticaria, rhinitis, asthma and anaphylaxis have all been reported in latex allergic individuals exposed to products derived from natural rubber latex.
Since no safe level of Hevea latex allergen exposure is known, avoidance is the primary mode of treating latex allergy.
As a result of investigations conducted by many scientists across the world, thirteen latex allergens have so far been identified and categorized by the Allergen Nomenclature Sub-Committee of the International Union of Immunological Societies (IUIS) as Hev b 1 to Hev b 13 (Table 1) (see Specification D1193). Reported sensitization rates for these allergenic Hev b proteins vary among the many reports as a result of differences in the study populations, IgE antibody assay methods and the quality of the Hev b allergens used as calibrators and quality control reagents in the analysis. Most studies, however, agree that Hev b 1 and Hev b 3 are important allergens for individuals (for example, children with spina bifida) who are exposed through mucosal contact as a result of multiple surgeries or latex catheter use for an extended period of time. Additionally, investigators performing sensitization studies also agree that Hev b 5 and Hev b 6.02 are important allergens that may elicit sensitization in genetically-predisposed individuals who are exposed to natural rubber latex (2-4). On the basis of these clinical studies, assays for these four allergenic proteins (that is, Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02) have been developed and they are thus the subject of this standard. Adoption of immunoenzymetric assay reagents and standard proteins needed to quantify other latex allergens (other than Hev b 1, 3, 5, and 6.02) in extracts of natural rubber latex products will require separate documentation and validation.
Scope
1.1 This test method covers an immunological method known as an immunoenzymetric assay to quantify the amount of 4 principal Hevea brasiliensis [Hev b] allergenic proteins [Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02] in natural rubber and its products derived from latex using monoclonal antibodies specific for epitopes on these proteins. Since these assays quantify the levels of only 4 of the known 13 officially acknowledged allergens potentially present in natural rubber latex containing products, the sum of the four allergen levels shall be viewed as an indicator of the allergen burden and not as a measure of the total allergen content that can be released from the product.
1.2 For the purpose of this test method, the range of allergenic protein will be measured in terms of nanogram to microgram quantities per gram or unit surface area of a natural rubber containing product.
1.3 The test method is not designed to evaluate the potential of natural rubber containing materials to induce or elicit Type I (IgE-mediated) hypersensitivity reactions.
1.4 This test method should be used under controlled laboratory conditions to detect and quantify the level of 4 allergenic proteins found in natural rubber containing products. It should not be used to describe, appraise or assess the hazard or risk of these natural rubber containing materials or products under actual in use conditions.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
