LAL Test

The LAL and rFC tests are based on a enzymatic cascade activated by endotoxin in horse shoe crabs. Much like the human blood coagulation- or complement system can become activated by invading bacteria, also horse shoe crabs possess innate immune reactivity to Gram-negative bacteria: endotoxin activates the conversion of Factor C into its activated variant, Factor C*. The LAL detects the resulting clotting reaction in limulus blood (hemolymph) either via a gel clotting- , or a turbimetric-, or a chromogenic read-out. In the rFc test, recombinant Factor C is used whereby its activation by endotoxin generates a fluorescent end product that can be detected.