Can the adenosine triphosphate (ATP) bioluminescence assay be used as an indicator for hospital cleaning? - A pilot study.

Background: In hospital cleaning, there is currently no standard for uniform monitoring of surface cleaning, either in Germany or internationally. One possibility for monitoring is the use of so-called objective methods for checking cleaning performance (e.g. fluorescence or adenosine triphosphate (ATP) method).

Aim: The aim of the study was to monitor and evaluate the implementation of the adenosine triphosphate (ATP) bioluminescence assay as a cleaning indicator in everyday hospital cleaning, in order to verify its utility and effectiveness.

Methods: In three phases, five frequently touched surfaces were examined with the ATP bioluminescence assay at different time points. 846 measurements were performed on the dermatology ward of a university hospital (phase 1), 1,350 measurements were performed on five different wards of the university hospital (phase 2), and 1,044 measurements were performed on five wards of another large hospital (phase 3). For this purpose, one structurally old and one structurally new ward as well as an intensive care unit (ICU), an outpatient clinic and a radiology department were selected for phases 2 and 3.

Results: With the ATP bioluminescence method, we were able to demonstrate a reduction in values after cleaning: before cleaning mean of ATP, 907 relative light units (RLU) (95% confidence interval [CI] 777; 1,038); after cleaning mean=286 RLU (CI=233; 495) (phase 1) and by intervention (five hours after daily cleaning mean=360 RLU (CI=303; 428); five hours after daily cleaning and two additional cleanings mean=128 RLU (CI=107; 152) (phase 3). The ATP values increased five hours after cleaning in phases 1 and 2, and eight hours after cleaning in phase 3. The structurally old wards had the highest ATP content, the ICU and the radiology department, among others, the lowest. In all phases, door handles showed both a reduction after cleaning or intervention and a subsequent increase in ATP values. Chair armrests, examination tables and door handles had high ATP values overall.

Conclusion: The study shows ward differences both for cleaning effects and for the soiling characteristics of surfaces during the course of the day. In addition, it demonstrates the benefit of intermediate cleaning twice a day. It is noteworthy that structurally old stations and older inventory were more heavily soiled and, in some cases, more difficult to clean. The results show that the ATP bioluminescence method is suitable for detecting cleaning effects and can be used in everyday clinical practice for simple cleaning monitoring. Furthermore, it enables the detection of risk surfaces and easy-to-clean surfaces with significant re-soiling.