Endotoxin testing

horseshoe crab

What are endotoxins and how do we test for them?

Bacterial endotoxins are lipopolysaccharides (LPS), components of Gram-negative bacterial cell walls, known to cause fevers and disease when injected into the bloodstream. To minimise the risk of these reactions, parenteral or injectable medicines are tested to ensure they are endotoxin free.

We use the Charles River Kinetic Chromogenic LAL Endotoxin Test System (Endosafe-PTS) - a single-step rapid testing system which includes assays for quick and quantitative endotoxin analysis, glucan contamination testing and gram identification.

The LAL test

Our endotoxin test is based on the limulous amoebocyte lysate test (LAL test). This test uses the LAL enzymes from the blood cells (amoebocytes) of the Atlantic horseshoe crab (Limulous) to bind and inactivate endotoxin from invading bacteria. Atlantic horseshoe crabs are native to South Carolina, and are protected to prevent over-harvesting. Charles River maintains a sustainable blood harvesting programme for obtaining the blood from these special creatures.

Find out more about how horseshoe crabs help to save lives:

Charles River website (external link)

More about horseshoe-crab blood (external link)