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°C compared with 60°C (100% vs 0% for PNCL, 17% vs 0% for TOSI, and 60% vs 22% for WC, 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°C cycles). Despite suboptimal cleaning cycles, all soiled tweezers looked clean.


CONCLUSIONS
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.
Diagnostic Services of Manitoba, Winnipeg, Manitoba, Canada; Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada; St Boniface Research Centre, Winnipeg, Manitoba, Canada. Electronic address: malfa@dsmanitoba.ca.
Michelle J
MJ
Alfa
St Boniface Research Centre, Winnipeg, Manitoba, Canada.
Nancy
N
Olson
D003666:Decontamination / Q000379:methods*; D003902:Detergents / Q000494:pharmacology; D004203:Disinfection / Q000379:methods*; D006796:Household Work / Q000379:methods*; D007202:Indicators and Reagents; D013696:Temperature; D013997:Time Factors
D003902:Detergents; D007202:Indicators and Reagents
Audit; Medical device reprocessing; Quality