Limulus amebocyte lysate (LAL) is a substance derived from the blood of the horseshoe crab, specifically from its amebocytes. This unique blood component is used primarily in medical testing to detect bacterial contamination in pharmaceuticals and medical devices. LAL reacts with bacterial endotoxins, producing a gel-like clot, which indicates the presence of harmful bacteria. The use of LAL is crucial in ensuring the safety of injectable drugs and surgical equipment. Because it is highly sensitive to endotoxins, it serves as a reliable method for quality control in the pharmaceutical industry, helping to prevent infections and ensure patient safety.