The Bacterial Endotoxins Test (BET) described in this chapter contains additional techniques using nonanimal-derived reagents to the Bacterial Endotoxins Test 〈85〉. This chapter is currently not an “applicable” chapter as described in General Notices, 3.10 Applicability of Standards. Unless specified in an individual monograph, the tests in this chapter are considered alternative tests and must meet the requirements in General Notices, 6.30 Alternative and Harmonized Methods and Procedures. This test uses a reagent containing the recombinant Factor C (rFC) protein or a recombinant cascade reagent (rCR) containing recombinant Factor C, recombinant Factor B, and recombinant proclotting enzyme. These reagents are used to detect or quantify endotoxins from Gram-negative bacteria in test samples. The test is performed using reagent(s) based on the gene sequence(s) of the relevant factors of the horseshoe crab (Limulus polyphemus, Tachypleus tridentatus, or Carcinoscorpius rotundicauda).