Review Notes DETAILS
According to AAMI, chemical indicators are defined as sterilization process monitoring devices designed to respond with a chemical or physical change to one or more of the physical conditions within the sterilizing chamber
Chemical indicators may be external or internal
AAMI categorizes CI into five classes
Class 1 Chemical Indicators fall under external indicators. They are used on the outside of every package to be sterilized.
They provide visual evidence to the user even before the package is opened.
A color change of the indicator gives an indication whether the item was either processed or not processed. The external CI usually reveals a visual color change that indicates a package was run in the sterilizer.
Class 1 CI come in the form of tapes, labels or load cards.
Example are indicators found on paper or plastic peel pouches.
Indicator tape is an example of an external CI and it simply indicates that a package was run in the sterilizer. Internal CIs are used to ensure the sterilant penetrated the packaging system
Class 2 chemical indicators are used in specific tests. Typical example is Bowie Dick test which is used to test a sterilizer for efficacy of air removal
Class 3 is a single parameter indicator designed to measure a single aspect of the sterilization process
Class 4 is a multi-parameter indicator are designed to react to two or more of the variables of the sterilization process
Class 5 indicators are referred to as integrators. They are designed to react to all critical parameters over a specified range of sterilization cycles
Class 5 integrating indicators provide the most comprehensive information. It demonstrates that ALL of the parameters necessary for sterilization were met for that specific cycle ran
The chemical integrator should be placed in an area of the package where it is most difficult to reach by the sterilant. This could be anywhere in the package, not necessarily the middle of the package.
A CI or BI could fail due to a number of reasons, more of which are operator error or negligence.
- Not storing the indicator with the proper temperature or humidity conditions
- Not following manufacturer’s instruction for use (IFU)
- Not using the correct sterilization cycle
- Overloading or wrong loading of packages
- Deficiencies of the sterilizing agent
- Malfunction of the sterilizer
In case of a sterilizer malfunction, the sterilizer must be taken out of service and the supervisor must be notified
AAMI guidelines state that an external and internal CI should be used with every pack. The FDA classifies CIs as Class II medical devices
CIs should be used on the outside and inside of all sterilized packages.