Healthcare Purchasing Online recently addressed the frequency of testing automated instrument cleaning units in their November on-line Q&A column.  In addition to discussing the current guidelines for the frequency of testing, they also mentioned the importance of the enzymatic detergent chemistry along with wash time, temperature and water chemistry.  In addition to the frequency of testing, it is also important to know the cleaning monitors/performance tests are affected by chemistry, water temperature, wash cycle and mechanical action of washer disinfectors and ultrasonic cleaners.