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The sterility assurance predicament:
There is no practical way of verifying the sterility of
individual objects that have been through a sterilizer.
Therefore, it is imperative that the three critical steps in
testing the efficacy of the sterilizer process is followed which
include: Physical monitoring, the use of external and internal CI
(chemical indicators) and the frequent use of BI’s (biological
indicators).
Physical Monitoring:
Includes the recording of the
sterilizer’s temperature, time and pressure on digital printouts,
recorders, displays and/or gauges. This provides real-time
assessment of the sterilization cycle and a permanent record in the
form of a chart or printed readout. Physical monitoring helps to
detect malfunctions sooner allowing you to take corrective actions.
Chemical Indicators: Chemical Indicators are a critical part of an
effective quality assurance program and should be used in
conjunction with physical monitoring and biological indicator
testing. Best practices recommend that external and internal CI’s
should be used for all items being sterilized. Chemical indicators
range from Class 1,2,3,4 and 5 as briefly described below: (See
Sterilization Supplies
for our
full line of
chemical indicators).
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Class 1 chemical
indicator: A process indicator often
referred to as an external indicator. They distinguish between
processed or unprocessed items and indicate that they were exposed
the sterilizer. These are seen as indicators
on pouches, sterilizer tapes or labels.
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Class 2 chemical
indicator: Is designed for a specific
test procedure (e.g. The Bowie-Dick test used to determine if air
removal has been adequate in dynamic-air-removal sterilizers)
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Class 3 chemical
indicator: Is a single parameter
indicator. It is designed to react to one of the critical
parameters of sterilization.
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Class 4 chemical
indicator: Is a multi-parameter
indicator. It is designed to react to two or more of the
critical parameters of sterilization.
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Class 5 chemical
indicator: Is an integrating indicator.
This chemical indicator reacts to all three parameters
of sterilization which include proper amount of time,
temperature and pressure of the sterilizer. They have been
correlated to the performance of a biological indicator when used
according to the manufacturers conditions noted on the label.
Biological Indicators: (Also known as spore tests or BI’s) are paper
filter strips inoculated with millions of spores. They provide the
only way the sterility process can be measured. Sterilizer
manufacturers validate their sterilizers by using biological
indicators, and therefore BI’s should be used to check the
sterilizer’s effectiveness frequently and on a routine basis. The
CDC, The Joint Commission,
AAMI and others are now recommending DAILY monitoring of sterilizers
using biological indicators (or at least each day the sterilizer is
being used).
It is also recommended that a
PCD be used when testing a
sterilizer. A “PCD” is a process challenge device. This device is
to be equal or greater than the most difficult item that is
routinely sterilized such as a large pack or tray. Often the device
is assembled ‘in-house’ using towels folded and stacked with a BI
(biological indicator) or CI (chemical indicator) in the center of
the stacked towels. A PCD should be representative of a package or
tray that routinely is processed through the sterilizer. PCD’s are
also sold commercially (see
Sterilization Supplies that are FDA cleared, although there
is no universally accepted PCD for table top sterilizers. PCD’s
that are commercially available present a challenge to your
sterilizer using a BI or CI in the center of the pack, but it may
not represent your own particular tray or pack, which is why we
recommend that the user sets up their own PCD “device” as noted
above. For more technical information, contact us at
info@autoclavesporetesting.com.
PROOF OF STERILIZATION CONCLUSION:
If your facility is following the guidelines as noted above and as
recommended by The CDC, The Joint Commission, and AAMI, and you have
documented Third-Party Laboratory results of biological and chemical
indicator test results, this will ensure you, your staff and your
clients that your sterilizer is functioning correctly and is in fact
sterilizing.
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