Bacterial Endotoxin Test (BET Test)

Overview…

The Bacterial Endotoxin Test, or Lumulus Amebocyte Lysate (LAL) Test, quantifies endotoxins that are part of the cell wall of gram-negative bacteria. Performed as a lot release test, the Bacterial Endotoxin or LAL Test assesses medical devices coming in contact with cerebrospinal fluid or the cardiovascular system

Definition…

Endotoxins are lipopolysaccharides found in the cell wall of Gram-negative bacteria, which can induce inflammation and fever as an immune response in higher organisms. Reaction to endotoxins can lead to anaphylactic shock and death of patients.

Introduction

There has been considerable discussion in the literature recently pertaining to the Bacterial Endotoxins Test, its significance and interpretation, and its comparison to the USP rabbit test. The topic was previously briefly addressed via Inspection Technical Guide No. 32, dated 1/12/79, with the subject: Pyrogens, Still a Danger.

Because of the increased acceptance and use of the Bacterial Endotoxins Test, ITG No. 32 is being updated.

The USP now recognizes two tests – The Pyrogen Test conducted with rabbits and the Bacterial Endotoxins Test, also termed the Limulus Amebocyte Lysate (LAL) Test. Additionally, the agency has approved the use of the Bacterial Endotoxins Test for many drug and device products. This ITG will focus on the significance and interpretation of pyrogen/endotoxin testing. Also sources and methods of depyrogenation will be discussed. The limitations of the rabbit pyrogen test should be recognized when reviewing systems during inspections of sterile drug and device manufacturers.

Purpose…

As an endotoxin is a type of pyrogen, both assays test for harmful Gram-negative bacteria that can produce life-threatening symptoms if introduced into the bloodstream or spinal fluid. The rabbit pyrogen test is an in vivo (performed inside of a living organism) test to detect pyrogens.

Injectable pharmaceutical products must also be tested for bacterial endotoxins. Routine monitoring of water systems and incoming materials can help to ensure that the process does not contribute endotoxins to the final product.

Bacterial endotoxin test (aka LAL test):
To detect or quantify endotoxin of gram negative bacterial origin using amoebocyte lysate from horseshoe crab (Limulus polyphemus or Tachypleus tridentatus)