Limulus Amebocyte Lysate (LAL)

Limulus Amebocyte Lysate (LAL) is a substance derived from the blood cells (amebocytes) of the horseshoe crab. It is highly sensitive to bacterial endotoxins—toxins from the outer membrane of certain bacteria—that can cause fever or sepsis in humans. When LAL detects these endotoxins, it triggers a rapid clotting response, allowing scientists to test pharmaceutical products and medical devices for contamination. Because of its effectiveness, LAL is a standard and essential tool in ensuring the safety of vaccines, IV fluids, and surgical instruments, preventing potentially dangerous bacterial endotoxin contamination.