Applicability of the ATP assay in monitoring the cleanliness of hospital environments.

Background: The adenosine triphosphate (ATP) assay is widely used for simple and rapid evaluation of the cleanliness of environmental surfaces. However, there remain concerns regarding the reliability of the ATP assay in hospital settings. This study aimed to assess whether the ATP assay could detect inadequate cleaning within hospital environments as well as monitor the effectiveness of routine cleaning.

Methods: The cleanliness of seven types of high-touch surfaces in operating rooms that were routinely cleaned was evaluated by testing the ATP assay and aerobic colony counts (ACC). For pressure redistribution mattresses (Soft-nurse®) that were found to be particularly at risk of infection, cleaning methods were improved, and the effectiveness of these improvements was monitored using the same two methods.

Results: The ATP assay quantitatively detected contamination on seven high-touch surfaces but showed no correlation with ACC. However, a significant positive correlation between luminescence and ACC was found on one specific surface, allowing for determining a theoretical cutoff value. Additionally, the ATP assay effectively identified the risk of future infection, which the ACC test could not assess.

Conclusions: The ATP assay can monitor the effectiveness of routine cleaning by setting a theoretical cutoff value for each subject. The method provides quantitative and meaningful values when used with an understanding of its limitations.