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International interlaboratory comparison of endotoxin assays using agricultural dusts.

Reynolds SJ; Thome P; Donham K; Croteau E; Kelly K; Milton D; Lewis D; Heederick D; Connaughton I; Larsson B; Malmberg P
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :31
Endotoxin from gram-negative bacteria pose a significant respiratory hazard. Establishing dose-response relationships is problematic since there are no standard procedures for sampling and analysis. The goal of this study was to evaluate the performance of six laboratories using Limulus·based assays for analysis for organic dusts from three agricultural environments. Dusts from chicken and swine barns and a corn processing facility were used to generate homogeneous aerosols in the laboratory. Fourteen side-by-side air samples were collected on 37 mm glass-fiber filters at flows of 2 L/min. Each laboratory was randomly allocated 14 filters per dust type. Three laboratories used the QCL-l000 Endpoint Assay, and three used the Kinetic-QCL method. To eliminate variability among different lots, a single lot of LAL for Endpoint Assays, and one similar lot for Kinetic Assays were provided. There were significant differences between laboratories for all three dust types (p<0.0l). The pattern of differences between labs varied by dust type. For chicken dust, labs using the Endpoint method reported higher results than those using Kinetic methods. For swine and corn dusts, the labs using the Kinetic method reported the highest endotoxin values. For chicken dust, results from all six labs were highly correlated (r=0.85 to 0.99). For swine dust, one lab (E) was not correlated, but the others were again highly correlated. For corn dust, four of the labs were significantly correlated. Most labs were within one standard deviation of the mean result for individual experiments. All labs were well within two standard deviations of the mean result for individual experiments. In conclusion, statistical differences in performance between laboratories were apparent and may be related to the extraction and analytical methods. The results of this study will be used to help develop a standardized sampling/analytical method for airborne endotoxin in agriculture.
Analytical-methods; Analytical-instruments; Laboratories; Laboratory-equipment; Laboratory-techniques; Laboratory-testing; Agriculture; Dust-analysis; Dust-measurement; Dust-sampling; Endotoxins; Standards; Statistical-analysis; Air-sampling-equipment; Air-sampling-techniques; Airborne-dusts; Airborne-particles; Kinetics; Bioassays; Testing-equipment; Equipment-reliability; Performance-capability; Organic-dusts; Bacterial-dusts; Aerosols; Filters
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American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia
Page last reviewed: April 1, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division