Comparison of adenosine triphosphate, microbiological load, and residual protein as indicators for assessing the cleanliness of flexible gastrointestinal endoscopes

BackgroundThis study evaluated 3 potential indicators of gastrointestinal endoscope cleanliness: adenosine triphosphate (ATP), microbiological load, and protein.MethodsBefore and after cleaning, ATP and microbiological load were determined from swabs of exterior surfaces and rinses of interior suction/accessory channels. Similarly, before and after cleaning, residual protein was determined from rinses of interior suction/accessory channels.ResultsBefore cleaning, ATP values were 10,417 relative light units (RLU) from the exterior endoscope surface and 30,281 RLU from the suction/accessory channel rinsates. After cleaning, these ATP values were decreased to 82 RLUs and 104 RLUs, a statistically significant difference. A similar trend was observed with microbiological load, but the change in residual protein from before cleaning to after cleaning was not significant. ATP values reliably reflected microbiological colony counts.ConclusionsATP measurement can provide a reliable, rapid and practical assessment of endoscope cleanliness for routine monitoring in the clinical setting.