MEASUREMENT OF NATURAL-RUBBER PROTEINS IN LATEX GLOVE EXTRACTS - COMPARISON OF THE METHODS

Background: Healthcare workers and individuals with frequent contact w ith latex are at risk for latex protein allergy. Objective: The purpos e of this study was to compare several established methods for measuri ng protein in extracts from latex-containing medical devices. Methods: Extracts from latex gloves were analyzed for natural rubber proteins using a modified Lowry assay and two different immunochemical assays. The immunochemical methods were competitive inhibition assays that emp loyed either immune rabbit serum or human serum with antibodies direct ed against natural rubber proteins. Results: Seventy extracts represen ting five different brands of gloves from four manufacturers were anal yzed. A good linear correlation (R = 0.88) was found between the immun oassay methods. Correlation to the modified Lowry method was not possi ble because many of the samples were below the limit of detection for the Lowry assay. Reference extracts and antisera were further characte rized by Western blot analysis. The data demonstrate that the proteins recognized by rabbit antisera and the proteins recognized by human Ig E are similar. The greatest difference in the immunochemical assays ap pears to be the relative binding of the antibody sources to high and l ow molecular weight natural rubber proteins in the reference extracts. Conclusions: The immunochemical assays are specific for latex protein s and provide a more sensitive and biologically relevant method for de termining protein levels in latex medical products.