Safety Window and Quality Control of Delayed Reprocessing for Flexible Endoscopes.

BACKGROUND: Delays between bedside pre-cleaning and manual reprocessing may impair endoscope cleaning, but acceptable delay intervals remain unclear. METHODS: Six types of endoscopes were contaminated with sheep blood, pre-cleaned, and manually cleaned after type-specific delays. Gastrointestinal endoscopes contaminated with sheep blood, fluorescent marker, and Escherichia coli were pre-cleaned with moisturizing or non-moisturizing enzymatic detergent and reprocessed after delays of 3, 8, or 24 hours. Protein residue, microbial recovery, borescope findings, and fluorescence were assessed at three stages: before manual cleaning, after manual cleaning, and after automated endoscope reprocessor (AER) processing. RESULTS: Cleaning pass rates declined when delays exceeded 2 hours for gastrointestinal endoscopes, therapeutic gastrointestinal endoscopes, and colonoscopes. Duodenoscopes were particularly affected, with pass rates decreasing to 20% at 2 hours and 0% at 2.5 hours. At an 8-hour delay, moisturizing detergent provided better microbial control than non-moisturizing detergent. All gastrointestinal endoscopes met the microbiological criterion after the complete AER cycle. DISCUSSION: Delayed reprocessing primarily impaired manual cleaning, particularly in structurally complex endoscopes. CONCLUSIONS: The findings support prompt manual cleaning and moisture retention when delays are unavoidable. The delay thresholds observed in this experimental model require clinical validation.