Recombinant Factor C (rFC) Assay
rFC is an endotoxin sensitive synthetic protein that is cloned from
factor C DNA to use as an alternative in vitro LAL test
47,63-67 . In the rFC test, the binding of endotoxin
activates the synthetic rFC molecule, which then cleaves a fluorescein
substrate (amino-methylcoumarin), resulting in the generation of a
fluorogenic compound. The fluorescence is measured twice, first at time
zero and then after the endotoxin has been introduced using
excitation/emission of 380/440 nm. The difference in fluorescence is
proportional to endotoxin concentrations in the sample and is used to
calculate a final endotoxin result. rFC is specific to endotoxin
detection eliminating the dependence on nonspecific glycan binding like
that in an LAL assay avoiding false positive
results.68 The enzymatic sensitivity range to
endotoxin is 0.05-500 EU/ml.63