In the mid 1970s, a number of medical device manufacturers began using the Limulus amebocyte lysate (LAL) test as an alternative to the United States Pharmacopeia (USP) rabbit test for pyrogen (bacteria endotoxins) testing of medical devices and administrative sets (1). The United States Food and Drug Administration (FDA) then provided conditions for the use of the LAL test as a sensitive indicator for the presence of bacterial endotoxins and as an alternative to the USP rabbit pyrogen test for medical devices in November 4, 1977 (2). Medical device manufacturers had to submit adequate data establishing equivalency of the USP rabbit test and the LAL test used. These data were then submitted to the FDA to obtain approval to use the LAL test. A key study reported by Mascoli in 1978 provided the answer to the question of nonendotoxin pyrogens (3). This study data confirmed that all pyrogens in fluids and devices were indeed bacterial endotoxins based on 28,410 rabbits tested and 143,196 LAL tests performed. The same study also concluded that there were no incidents of unexplained false negative LAL test results, that the LAL test was more sensitive in detecting endotoxins then the rabbit test, and that the LAL test was also equally reproducible to theUSP rabbit test.