I have noticed that a few articles have been published recently questioning the use of recombinant Factor C (rFC) assays to detect endotoxin contamination in parenterally administered pharmaceuticals or implanted medical devices [Editor’s Note: See list of previous rFC-related articles at end of article.]. There seems to be some confusion regarding the history of the development of the limulus amebocyte assay (LAL) assay, the development of the rFC assay and its regulatory status.