Bacterial Endotoxin Testing: The LAL Assay

Mitigating risk to patients and complying with regulatory standards is vital in the pharmaceutical and biomedical industries. One crucial aspect of risk management is to ensure that any parenteral medicines and implantable devices released to the market are not contaminated with harmful bacterial endotoxins. As an essential requirement of current Good Manufacturing Practices (cGMP) and other quality control regulations, many companies use LAL testing to detect the presence of endotoxins in their products throughout the manufacturing processes. Often, companies will also test the raw materials for endotoxins before manufacturing begins, to meet Quality by Design criteria and assure low or negligible endotoxin content in raw material if possible.
Endotoxin-testing-in-the-lab
The LAL assay is known to be a powerful endotoxin test with high reliability, sensitivity and specificity. It is one of the BET approaches recommended by leading regulatory authorities. LAL testing is used in a wide range of applications, including in pharmaceutical preparation testing, and on-site tests of short-lived radioisotopes.

In the US, the LAL assay relies on a reagent made from the harvested blood of wild Atlantic horseshoe crabs (Limulus polyphemus) that inhabit eastern coastal areas. In south-eastern and eastern Asia, three other horseshoe crab species (Tachypleus spp.) are harvested for their blood to produce another type of BET reagent, known as TAL. However, the TAL reagent is used in Asia, while LAL is used worldwide.