Bacterial Endotoxin Testing

Endotoxins are lipopolysaccharides (LPS), large molecules consisting of a lipid and a polysaccharide, that are found in the outer membrane of Gram-negative bacteria. Endotoxins are released after destruction of the bacterial cell wall or secreted in the form of bacterial outer membrane vesicles. In contrast to bacteria endotoxins are very heat stable even after sterilization. They induce strong responses from animal immune systems, e.g. inflammation. There are two standard tests for endotoxin testing, LAL Test and Haemotox rFC.

LAL (Limulus amebocyte lysate) is an extract of blood cells from the Atlantic horseshoe crab (limulus polyphemus). LAL reacts with the bacterial endotoxin lipopolysaccharides, which can be detected by gel-clot, turbidimetric, or chromogenic methods.

Haemotox rFC is a recombinant endotoxin receptor (factor C) that is alternatively used to limulus amebocyte lysate. The reaction is measured via highly sensitive fluorescence detection. This new test appears to be more accurate than the traditional LAL test.

Material requisition: 1.5 mg/sample

Time needed: 2 weeks