The "total extractable protein" (TEP) assay (also commonly known as the "modified Lowry" method) measures the total amount of protein in an extract made from the glove, and is presently being considered as the standard test method for measuring protein levels in gloves for Part 3 of EN-455 Citation:prEN 455-3 (the European standard for medical gloves). Whilst is can be criticised for measuring all the extractable protein in the glove (and not just the allergenic proteins which cause the Type I reaction) it appears to be a useful indicator of whether the gloves are likely to produce Type I reactions. Yip et al Citation:Yip Turjanmaa Ng Mok 1994 show that there is quite good correlation between TEP and allergic reactions in individuals showing latex hypersensitivity. Whilst it has not yet been possible to determine a threshold level below which a latex sensitised individual will not experience an allergic reaction, their data demonstrates that at TEP levels of 400 µg/g, only 60% of the 59 latex sensitised subjects experienced an allergic reaction. They conclude that for even higher negative responses, TEP content should preferably be less than 100µg/g.
Pete Phillips <pete@smtl.co.uk>