Q. Show the Chemical indicators used in sterilization cycle?

Chemical indicators indicate the presence of certain conditions during the sterilization cycle, such as the presence of heat and steam. There are five classifications of indicators recognized by the FDA, and it is important to note that it is now recommended that all packs or cassettes include internal and external indicators.

Class 1 - Process Indicators. These are placed on the outside of packs and are useful in determining which packs have been properly processed versus those that have not. Class 1 process indicators include autoclave tape and the colour change indicators embedded on the outside of sterilization packaging materials.

Class 2 - Bowie-Dick Indicators. These show the pass/fail in prevacuum sterilizers. This test is conducted daily with the chamber empty, during the first cycle of the sterilizer, and is available as a kit from commercial sterilization monitoring companies.

Class 3 - Temperature-Specific Indicators. These react to one of the critical parameters of sterilization and indicate exposure to a specific value such as temperature or psi.

Class 4 - Multi-parameter Indicators. These react to two or more of the critical parameters in the same manner as Class 3 indicators.

Class 5 - Integrating indicators. These are designed to react to all critical parameters of sterilization cycles. When used properly, integrating indicators may serve as the basis for the release of processed items, excluding implants. It is important to follow the manufacturer's specific instructions for use regarding a test challenge pack.