Chemical indicators for autoclaves and steam sterilizers play a critical role in sterility assurance programs. There are many types of chemical indicators, such as bowie dick test packs and chemical indicator strips.
All chemical indicators are designed to respond to physical conditions inside the sterilizing chamber. This validates that an autoclave or steam sterilizer is working properly. It also verifies that it met the conditions for sterilization to occur.
Standards for Chemical Indicators
The International Organization for Standardization (ISO) issues many standards for sterilization processes. Chemical indicators must adhere to these manufacturing and application standards, and guidance documents.
ISO 11140-1:2014 is identical to:
- BS EN ISO 11140-1:2009
- ANSI/AAMI/ISO 11140-1:2014
ISO 11140-1:2014 replaces previous standards:
- EN867-1
- ANSI/AAMI ST60:1996
The most current standard is ISO 11140-1:2014. It defines 6 different types of chemical indicators for sterilization.
6 ISO Types of Chemical Indicators for Steam Sterilization
ISO 11140-1:2014 classifies chemical indicators for autoclaves and sterilizers as follows:
- Type 1: Process Indicators
- Type 2: Specific-Use Indicators
- Type 3: Single-Variable Indicators
- Type 4: Multi-Variable indicators
- Type 5: Integrating Indicators (Integrators)
- Type 6: Emulating Indicators (Cycle Verification Indicators)
The types are not ranked by level of importance. Type 1 is not better than type 6. Each type simply denotes performance characteristics and intended use of chemical indicators.
ISO 11140-1:2014 section 4.1
"The classification structure used is solely to denote the characteristics and intended use of each type of indicator when used as defined by the manufacturer. This classification has no hierarchical significance."
Since performance requirements are distinct, chemical indicators should only comply with one type. This chart summarizes the different ISO types of chemical indicators. It also provides examples of applications and STERIS Life Sciences products available for each type. Use it to help choose the correct chemical indicator for monitoring specific sterilization processes.
