Geert Verdonk, Merck/Schering Plough, presented his validation studies using the Charles River Laboratories Endosafe PTS. Dr. Verdonk explored the use of this rapid and portable endotoxin detection system as part of Merck’s PAT-RMM program in an API production environment. Parallel testing on endotoxin spiked samples was conducted against the gel-clot and turbidometric endotoxin procedures. Robustness testing was also evaluated using different operators, sample temperatures, sample volumes, and after “rough treatment” of the system (i.e., after touching the test cartridges, reservoirs and optical cells). The system is now fully implemented and has recently been used to support a root cause investigation in contaminated use points from a purified water system. Geert Verdonk, Merck/Schering Plough, presented his validation studies using the Charles River Laboratories Endosafe PTS. Dr. Verdonk explored the use of this rapid and portable endotoxin detection system as part of Merck’s PAT-RMM program in an API production environment. Parallel testing on endotoxin spiked samples was conducted against the gel-clot and turbidometric endotoxin procedures. Robustness testing was also evaluated using different operators, sample temperatures, sample volumes, and after “rough treatment” of the system (i.e., after touching the test cartridges, reservoirs and optical cells). The system is now fully implemented and has recently been used to support a root cause investigation in contaminated use points from a purified water system.