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LPC Snapshot March 2023


Endotoxin Testing and Validation


Sufira Kiran, DCLS, BS, MLS(ASCP)CM

Associate Director, Quality Assurance

Uthealth Science Center

Houston, TX

Bacterial endotoxin is a toxin found in the outer membrane of gram-negative bacteria. It can be detected by an assay that combines a liquid test sample with a Limulus Amebocyte Lysate (LAL) reagent and measures the resulting proportional reaction via visual, turbidimetric, or chromogenic means of detection. The FDA, USP, and EP guidelines are available on storage/handling, interference testing, and qualification of products for bacterial endotoxin testing. For product validation, specific parameters need to be calculated, such as Endotoxin Limit (EL), Maximum Valid Dilution (MVD), or Maximum Concentration Dilution. The Endotoxin product validation is necessary on all cell types to identify a dilution/concentration that neither inhibits nor enhances the endotoxin testing. Then, that defined dilution or concentration can be used to test the specific product type for endotoxin assay.

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