At the recent 165th session of the European Pharmacopoeia (Ph.Eur) Commission, Bacterial endotoxin testing (BET) by recombinant factor C (rFC)  was designated as a new general chapter to come into effect on the 1st January 2021. The animal-free alternative to testing with the lysate of horseshoe crabs had previously been described on its use as an alternative to Limulus amebocyte lysate in Supplement 8.8 in Chapter 5.1.10 'Guidelines for Using the Test for Bacterial Endotoxins'.

bioMérieux and Lonza both have rFC products on the market. The Lonza PyroGene™, for example, is based on a recombinantly produced form of Factor C (rFC), the first component in the horseshoe crab clotting cascade, and the first enzyme to react in all endotoxin detection assays. In the PyroGene™ rFC Assay, the activated recombinant Factor C enzyme cleaves a substrate directly instead of activating another enzyme in the series (the LAL cascade). The substrate is a fluorescent tag, which gives a wide dynamic range with better resolution.