5.1 Type 1 latex allergy most commonly manifests as localized urticaria after contact of skin with natural rubber but can also include symptoms of allergic rhinoconjunctivitis, asthma and rarely anaphylaxis. This immediate (Type I) allergy is caused by HNRL proteins inherent to the rubber tree, which remain on the finished products. The quantification of protein levels in HNRL products using the standard colorimetric protein assays may give spurious results due to chemical additives in the latex formulations that interfere with the assay (2,3). Furthermore, the amount of protein found in HNRL products are often below the detection limits of the standard colorimetric protein assay (4,5).

5.2 This test method describes an immunological method for quantitation of HNRL proteins using rabbit anti-HNRL serum. Rabbits immunized with HNRL proteins react to the majority of the proteins present, and their sera have the capability to detect most if not all of the proteins in HNRL. Therefore, although rabbit antibody reacts with antigenic material, this should not be considered as quantitative measure of total protein levels.

1.1 This test method covers an immunological method to determine the amount of antigenic protein in Hevea Natural Rubber and its products using rabbit antisera specific for HNRL proteins. This immunoassay procedure quantitatively measures the level of antigenic latex proteins in solution using an inhibition format. The samples may include glove or other product extracts which have been collected in order to measure the HNR levels. Although this method detects antigenic proteins, it should not be considered as a measure of allergenic proteins. Correlation of protein/antigen levels with the level of allergenic proteins has not been fully established.

1.2 For the purpose of this test method, the range of protein will be measured in terms of microgram to milligram quantities.

1.3 This test method can be used to determine the presence and amount of HNR protein contamination on test items.

1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.