Safety Window and Quality Control of Delayed Reprocessing for Flexible Endoscopes

Delays between bedside pre-cleaning and manual reprocessing may impair endoscope cleaning, but acceptable delay intervals remain unclear.

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.

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.

Delayed reprocessing primarily impaired manual cleaning, particularly in structurally complex endoscopes.

The findings support prompt manual cleaning and moisture retention when delays are unavoidable. The delay thresholds observed in this experimental model require clinical validation.