Second inter-laboratory study comparing endotoxin assay results from cotton dust.

Previously, a large two-part inter-laboratory round robin endotoxin assay study was completed. This first study showed that when cotton dust samples, which are practically identical, are assayed for endotoxin that the intra- laboratory results had a very small variation while intra-laboratory results of the sample had a very high variation. In the first part of the study, each laboratory followed its own in-house assay protocol; but in the second part of the study, when the extraction protocol was standardized, the inter-laboratory results showed a lower variation, which suggested that with further standardization, further reduction of differences between laboratories might be achieved in order that results between laboratories would become more comparable.