Assessment of test methods for evaluating effectiveness of cleaning flexible endoscopes

Strict adherence to each step of reprocessing is imperative to removing potentially infectious agents. Multiple methods for verifying proper reprocessing exist; however, each presents challenges and limitations, and best practice within the industry has not been established. Our goal was to evaluate endoscope cleaning verification tests with particular interest in the evaluation of the manual cleaning step. The results of the cleaning verification tests were compared with microbial culturing to see if a positive cleaning verification test would be predictive of microbial growth.

This study was conducted at 2 high-volume endoscopy units within a multisite health care system. Each of the 90 endoscopes were tested for adenosine triphosphate, protein, microbial growth via agar plate, and rapid gram-negative culture via assay. The endoscopes were tested in 3 locations: the instrument channel, control knob, and elevator mechanism.

This analysis showed substantial level of agreement between protein detection postmanual cleaning and protein detection post-high-level disinfection at the control head for scopes sampled sequentially.

This study suggests that if protein is detected postmanual cleaning, there is a significant likelihood that protein will also be detected post-high-level disinfection. It also infers that a cleaning verification test is not predictive of microbial growth.