What is endotoxin testing (LAL assay)?
Endotoxin testing detects lipopolysaccharide from the outer membrane of Gram-negative bacteria, most often with the Limulus amebocyte lysate (LAL) assay described in USP chapter <85>.
Why endotoxin matters
Endotoxin is a component of Gram-negative bacterial cell walls. It persists after bacteria are killed, so it can be present even in material that contains no living organisms. Testing screens material for this form of bacterial contamination.
How the LAL assay works
The assay uses a reagent derived from horseshoe crab blood cells that reacts in the presence of endotoxin. Results are reported against an assay sensitivity in endotoxin units per milliliter (EU/mL). The U.S. FDA's guidance on pyrogen and endotoxin testing describes the gel-clot, photometric and kinetic forms of the test.
Endotoxin results for IGF-1 LR3
Lots without endotoxin testing are marked "Not tested" in the COA archive.
Limits
A pass means endotoxin was below the assay threshold in the sample tested. It applies only to that lot.