I admit it that there are times I can come across as
being too zealous, but when I truly believe an injustice is occurring, then I
need to do everything in my powers to ensure the issue is addressed. The widespread misuse of ATP
(Adenosine Triphosphate) as a means for
comparing the effectiveness of different disinfectants is something that I
cannot leave unaddressed. To me it’s the
equivalent of trying to force a square peg into a round hole or for that matter
trying to use margarine to make shortbread....when butter is the only way to
go!
being too zealous, but when I truly believe an injustice is occurring, then I
need to do everything in my powers to ensure the issue is addressed. The widespread misuse of ATP
(Adenosine Triphosphate) as a means for
comparing the effectiveness of different disinfectants is something that I
cannot leave unaddressed. To me it’s the
equivalent of trying to force a square peg into a round hole or for that matter
trying to use margarine to make shortbread....when butter is the only way to
go!
Don’t get me wrong, safe and effective disinfection of
high-touch environmental surfaces is an important tool in reducing the spread
of HAIs and the need for rapid and reliable means of monitoring the
effectiveness of such practices are also crucial for training and quality
control. I do agree that ATP has its
use; however, there are several limitations to the use of ATP within healthcare
facilities. First, the absence of
standardization of the ATP technology from various manufacturers and RLU
readings for use within healthcare makes cross-comparisons of readings and
benchmarking problematic. Second, the
lack of documented correlation between ATP readings and levels of microbial
contamination on environmental surfaces makes meaningful interpretation of the
data difficult and distinction between pathogenic and non-pathogenic microbes
on the sampled surface virtually impossible. Also, ATP kits cannot detect or
measure viral contamination because viruses possess no ATP. Third, and quite importantly, certain common
surface disinfectant chemistries and cleaning tools may interfere to varying
degrees with ATP measurements.
Therefore, the use of ATP as a tool to determine the effectiveness of
different cleaning practices or to compare the effectiveness of different
cleaning and disinfectant chemistries remains a challenge.
high-touch environmental surfaces is an important tool in reducing the spread
of HAIs and the need for rapid and reliable means of monitoring the
effectiveness of such practices are also crucial for training and quality
control. I do agree that ATP has its
use; however, there are several limitations to the use of ATP within healthcare
facilities. First, the absence of
standardization of the ATP technology from various manufacturers and RLU
readings for use within healthcare makes cross-comparisons of readings and
benchmarking problematic. Second, the
lack of documented correlation between ATP readings and levels of microbial
contamination on environmental surfaces makes meaningful interpretation of the
data difficult and distinction between pathogenic and non-pathogenic microbes
on the sampled surface virtually impossible. Also, ATP kits cannot detect or
measure viral contamination because viruses possess no ATP. Third, and quite importantly, certain common
surface disinfectant chemistries and cleaning tools may interfere to varying
degrees with ATP measurements.
Therefore, the use of ATP as a tool to determine the effectiveness of
different cleaning practices or to compare the effectiveness of different
cleaning and disinfectant chemistries remains a challenge.
While we have written a Technical Bulletin addressing
each of the limitations, it’s the limitation in the use of ATP as a comparator
tool that catches in my “caw” so to speak.
From an infection control perspective, we want to ensure that we choose
the best disinfectant for our programs so the ability to create numbers to
compare different disinfectants is of great interest. Unfortunately, in our attempts to generate
numbers, we have overlooked the limitations of the ATP test itself.
each of the limitations, it’s the limitation in the use of ATP as a comparator
tool that catches in my “caw” so to speak.
From an infection control perspective, we want to ensure that we choose
the best disinfectant for our programs so the ability to create numbers to
compare different disinfectants is of great interest. Unfortunately, in our attempts to generate
numbers, we have overlooked the limitations of the ATP test itself.
The issue of different cleaning chemistries and their
potential to enhance or quench ATP bioluminescence is especially
significant. Quats and anionic
surfactants, for example, may give false positive results by enhancing RLU
readings by as much as 10%. One study
with Hydrogen Peroxide showed that concentrations of 0.1% did not have any
enhancing or quenching effects on the RLU levels; at 0.5%, quenching effects of
3 - 5% were observed. On the other hand, chlorine has been shown to have both
enhancing and quenching effects. At
concentrations of 100 ppm chlorine has been shown to significantly enhanced RLU
readings. As concentrations increased
to 500 ppm neither quenching or enhancing effects were observed, but as levels
of chlorine increase to those (e.g., 1,000-5,000 ppm), routinely used for environmental surface
disinfection in healthcare facilities there may be as much as a 40% deviation
in quenching, thereby potentially giving false negatives! Consequently, Boyce et al in their study on
the use of ATP for monitoring the effectiveness of hospital cleaning excluded
all those rooms which were disinfected with a 5,000 ppm bleach solution.
potential to enhance or quench ATP bioluminescence is especially
significant. Quats and anionic
surfactants, for example, may give false positive results by enhancing RLU
readings by as much as 10%. One study
with Hydrogen Peroxide showed that concentrations of 0.1% did not have any
enhancing or quenching effects on the RLU levels; at 0.5%, quenching effects of
3 - 5% were observed. On the other hand, chlorine has been shown to have both
enhancing and quenching effects. At
concentrations of 100 ppm chlorine has been shown to significantly enhanced RLU
readings. As concentrations increased
to 500 ppm neither quenching or enhancing effects were observed, but as levels
of chlorine increase to those (e.g., 1,000-5,000 ppm), routinely used for environmental surface
disinfection in healthcare facilities there may be as much as a 40% deviation
in quenching, thereby potentially giving false negatives! Consequently, Boyce et al in their study on
the use of ATP for monitoring the effectiveness of hospital cleaning excluded
all those rooms which were disinfected with a 5,000 ppm bleach solution.
I’m not saying it’s wrong to use or that we should not
use ATP measurement kits to assess the degree of cleanliness of cleaned and disinfected
surfaces in healthcare settings. I am
simply asking that caution is used in the interpretation of the results because
several published studies have now documented the potential of cleaning tools
and disinfectant chemistries to either enhance or suppress the levels of RLU
and may in fact lead to either an over-estimation or an under-estimation of the
surface decontamination procedures in place.
use ATP measurement kits to assess the degree of cleanliness of cleaned and disinfected
surfaces in healthcare settings. I am
simply asking that caution is used in the interpretation of the results because
several published studies have now documented the potential of cleaning tools
and disinfectant chemistries to either enhance or suppress the levels of RLU
and may in fact lead to either an over-estimation or an under-estimation of the
surface decontamination procedures in place.
Just as making a good shortbread requires butter, if you
want to really know how well a disinfectant is working (e.g. killing the bugs)
you need to conduct microbiological testing.
want to really know how well a disinfectant is working (e.g. killing the bugs)
you need to conduct microbiological testing.
Bugging Off!
Nicole
