Endotoxin

Endotoxins are heat-stable molecules from the outer membrane of certain bacteria. They can confound laboratory results, so research-grade material is often screened for endotoxin using an assay such as LAL (Limulus Amebocyte Lysate) and reported against a defined limit.

An endotoxin result on a COA indicates the lot was tested and fell within the stated threshold — another layer of batch-level documentation beyond identity and purity.