USP Method <85>: Endotoxins

Bacterial endotoxins are a component of the cell wall of Gram-negative bacteria. The Bacterial Endotoxins Test (BET) is an assay used to detect or quantify endotoxins from Gram-negative bacteria. This test is also known as the Limulus Amoebocyte Lysate (LAL) test or the “pyrogen” test due to the ability of endotoxins to cause fever in mammals.  It is important that the USP <85> BET test not be confused with the rabbit pyrogen test, USP <151>. Endotoxin testing can be performed on raw and in-process materials as well as for the final release of pharmaceutical and medical device products.

The Gel-Clot Technique

The LAL gel-clot endotoxin test technique is used for detecting or quantifying endotoxins within a sample based on clotting of the lysate reagent in the presence of endotoxin.

Preparatory Testing
The USP <85> preparatory test is used to confirm labeled lysate sensitivity and any interfering factors.