Comparison of washer-disinfector cleaning indicators: Impact of temperature and cleaning cycle parameters

Background: Because automated instrument washer-disinfectors (WD) are widely used in health care to reprocess a variety of medical instruments, we developed a study to compare 3 cleaning indicators to determine whether they detected suboptimal temperature, time, enzymatic detergent, and fluid action in a washer-disinfector. Methods: The Miele WD was used for this comparison. One optimal cycle and 14 cycles with suboptimal enzymatic detergent, cleaning time, temperature, or inactive spray arms were evaluated. The cleaning indicators evaluated included the following: Pinnacle Monitor for Automated Enzymatic Cleaning Process (PNCL), Wash-Checks (WC), and TOSI. The scoring system for all 3 indicators was harmonized to a common scale. Soiled tweezers were included in each cycle evaluated. Results: The PNCL, TOSI, and WC cleaning indicators showed significantly more failures at 40 degrees C compared with 60 degrees C (100% vs 0% for PNCL, 17% vs 0% for TOSI, and 60% vs 22% forWC, respectively). There were significantly more failures at suboptimal temperatures with a 2-versus 4-minute cycle (100% vs 0% for PNCL, 17% vs 0% for TOSI, and 17% vs 0% for WC, respectively, for 40 degrees C cycles). Despite suboptimal cleaning cycles, all soiled tweezers looked clean. Conclusion: All 3 cleaning indicators responded to suboptimal WD conditions; however, the PNCL was the most affected by alterations in the cycle conditions evaluated. In simulated use testing, cleaning indicators provided a more sensitive audit tool compared with visual inspection of soiled instruments after automated cleaning. Copyright (C) 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.