Reliability Testing for Portable Adenosine Triphosphate Bioluminometers

Abstract

Measurement of adenosine triphosphate (ATP) using portable bioluminometers has been adapted from the food manufacturing sector, and it has been suggested that it could be used as an indicator of surface soiling or cleanliness in hospital settings. Some healthcare authorities are considering the use of portable ATP bioluminometers as a tool for standard setting for surface cleanliness to improve cleaning standards. Central to this approach is the use of a commonly accepted level of detected ATP—expressed as relative light units (RLUs)—that may be used as a surrogate for underlying soiling, including the presence of pathogenic microorganisms.It has been demonstrated that improvements can be made to cleaning processes with fluorescent markers through a simpler approach that provides a qualitative efficiency measurement of the cleaning process. Measurement of surface hygiene using ATP bioluminometers is thought to provide a more quantitative surrogate of surface cleanliness.

Failure analysis in the identification of synergies between cleaning monitoring methods

“…38 There is also a need for a monitoring process that has the role of quantitation of cleaning performance in terms of surface cleanliness, and rapid ATP testing could be developed to fill this void, subject to interpretation and validation issues. 8,[31][32][33][34][35][36] Not 1 of the current cleaning monitoring methods could overcome all of the potential failure modes that were identified for that monitoring method when considered in isolation.…”

“…6,[31][32][33] The failure modes identified from our FMEA, which are categorized as medium risk, are noted in Table 2.…”

“…8,36,37 Difficulties interpreting the results of ATP are a medium risk failure mode that underscores the importance of validation and training. 16,31,33 Mitigations noted against ATP testing are the adjunct use of microbial recovery methods and FM to indicate the frequency of cleaning on relevant environment surfaces, a validated sampling plan, and appropriate levels of training in the use an interpretation of ATP readings. 32 …”

A suggested sampling algorithm for use with ATP testing in cleanliness measurement

“…A Cv as high as 0.4 will also occur in normal field usage. Based on the work of Reed et al a Cv of 0.4 suggests that any two measures from the identical surface could differ by a factor of 1.5 or more in nearly half of all trials and differ by a factor of 2 or more in 1 in every 5 trials [23]. In such cases, a reading of 50 RLU and 100 RLU could be generated from the same surface cleanliness and still represent the same result [24,25].…”

“…In addition to brand differences between ATP testing devices there is a problem with inherent variability. Precision is the ability of the ATP testing device to repeatedly provide the same RLU reading at the same ATP [18,23].…”