If a contaminated batch sits in a holding tank for 48 hours, and the endotoxin becomes undetectable, the QC lab will release a product that is potentially pyrogenic to patients. LER thus represents a critical patient safety risk.
LER occurs when spiked endotoxins in certain biologics cannot be fully recovered or detected during testing, even when using the standard assay. This masking typically happens in biopharmaceutical formulations that combine: Surfactants (like Polysorbate 80) Chelating agents (such as citrate or phosphate buffers) pda technical report 82