How clean is clean enough? An observational pilot study to assess central sterilization processing efficacy with adenosine triphosphate levels

Background: There is strong evidence showing the need for quantitative assessment of the efficacy of cleaning medical devices. Studies comparing visual and microscopic analysis have demonstrated that visual inspection alone is insufficient to determine cleanliness. Our objective was to: collect baseline adenosine triphosphate testing data for surgical instruments to inform future quality improvement programs, and to develop a process to comply with standards recommended by the Association for the Advancement of Medical Instrumentation. Methods: The central sterilization processing department (CSPD) identified difficult to clean tools in hip, spinal fusion, and colon procedures. Instruments used during the procedures were swabbed at arrival to the CSPD, after manual washing, and after a standard 24-minute machine wash cycle. Each instrument was swabbed in a uniform manner on surface areas including hinged joints and teeth, consistent with manufacturer recommendations. Instruments were tagged to ensure accuracy of tracking. Results: The mean relative light unit (RLU) readout of all instruments on entry to the CSPD, postmanual wash, and postmachine wash was 240,416, 3,352, and 47, respectively. A total of 97.7% of all instruments had a passable final RLU readout. One Rongeur had a failed final RLU readout of 171. Conclusions: This study suggests that the current cleaning process is adequate for the instruments tested. Ongoing quality assessment would be beneficial to validate other instruments.