Is it really clean? An evaluation of the efficacy of four methods for determining hospital cleanliness

An important component of effective cleaning in hospitals involves monitoring the efficacy of the methods used. Generally the recommended tool for monitoring cleaning efficacy is visual assessments. In this study four methods to determine cleaning efficacy of hospital surfaces were compared, namely visual assessment, chemical (ATP) and microbiological methods, i.e. aerobic colony count (ACC) and the presence of meticillin-resistant Staphylococcus aureus. Respectively, 93.3%, 71.5%, 92.1% and 95.0% of visual, ATP, ACC and MRSA assessments were considered acceptable or 'clean' according to each test standard. Visual assessment alone did not always provide a meaningful measure of surface cleanliness or cleaning efficacy. The average ATP value from 120 swabs before cleaning was 612 relative light units (RLU) (range: 72-2575) and 375 RLU after cleaning (range: 106-1071); the accepted standard is 500 RLU. In a hospital setting with low microbiological counts, the use of chemical tests such as ATP may provide additional information of cleaning efficacy and ATP trends allow identification of environmental surfaces that require additional cleaning or cleaning schedule amendments. (c) 2009 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.