Endotoxins are complexes associated with the outer membrane of Gram-negative bacteria which are constantly shed into the environment and released when the bacteria die or multiply. Bacterial endotoxins are the most common and by far the most potent pyrogen. (Pyrogen literally means heat generating, and the term refers to any substance, microbial or otherwise, which would induce a temperature rise when introduced into a patient). Commonly used methods of sterilisation generally do not destroy endotoxins; therefore, a product may be sterile and free of viable microorganisms but not necessarily endotoxin-free.
Regulatory authorities require every batch of sterile products labelled as 'Non Pyrogenic' or 'Low Endotoxin' to be tested for pyrogens to a specified limit. Where limits are not available, endotoxin testing may be used for any application that requires information on the presence of Gram-negative bacteria or endotoxins. Since endotoxins may remain long after the destruction of bacteria, the test can be used to look at the history of the sample and therefore serves as a useful tool for in-process monitoring of endotoxin levels.
SMTL use the established pharmacopeial Limulus Amebocyte Lysate (LAL) quantitative kinetic turbidimetric method for analysing samples for endotoxins. This method determines the total amount of endotoxin in a sample and therefore is more useful than the gel clot method which gives a pass/fail result.
SMTL are UKAS accredited and have experience in testing a range of medical devices as well as the water used in the processing of devices.
If you have a product you wish to have tested or have any questions, please contact smtl.info@wales.nhs.uk
Relevant Stanards