Exploring Types of Chemical Indicators for Steam Sterilization: A Guide to ANSI/AAMI/ISO-11140:2014
Chemical indicators play a crucial role in steam sterilization processes by monitoring and verifying the necessary parameters for effective sterilization. We will delve into the different types of chemical indicators defined by ANSI/AAMI/ISO 11140-1:2014, Sterilization of Health Care Products – Chemical Indicators – Part 1: General Requirements. By understanding the various types of chemical indicators healthcare professionals can ensure the safety and reliability of their sterilization practices.
Purpose and Significance of Chemical Indicators in Steam Sterilization
Chemical indicators serve as pack and load monitors for sterilization processes. We’ll explore their vital role in distinguishing processed and unprocessed units, monitoring critical variables, and providing an added layer of assurance in sterilization procedures.
Type* 1 Chemical Indicators (Process Indicators)
Type 1 indicators appear on the outside of packages and indicate the exposure of individual units, such as packs or containers, to the sterilization process. While they don’t confirm the sterility of the pack’s contents, they offer a visual signal that the pack has come into contact with the sterilant. These indicators, known as external indicators, are affixing to the outside of packages and are commonly available as indicator tape, dots, or tray locks. They typically feature color changing ink after exposure to the sterilant. Process Indicators provide an easily identifiable indication of whether each unit has initiated the sterilization process.
Type 2 Chemical Indicators (Bowie-Dick Test Indicators)
Bowie-Dick tests, classified as type 2 chemical indicators, are crucial in assessing the efficiency of air removal in pre-vacuum steam sterilization processes. They serve as diagnostic tests, evaluating the dynamic-air-removal steam sterilizer’s capability to effectively eliminate air from the chamber. Bowie-Dick Test Packs simulate challenging load conditions, including air pockets, ensuring optimal air removal by the sterilizer. Bowie-Dick Test Packs contain porous and non-porous materials, along with a strip or card. They undergo a color change during the sterilization cycle when exposed to specific temperature and pressure conditions, signifying successful air removal. Sterile Processing Professionals routinely use Bowie-Dick test packs to validate the performance of sterilization equipment and uphold patient safety.
For routine sterilizer testing, simply place the Bowie-Dick Test Pack into an empty chamber and run a pre-vacuum steam sterilizer cycle before the first processed load of the day. This daily test forms an integral part of the sterilizer’s release criteria to ensure consistent efficacy. Additionally, Bowie-Dick test packs play a vital role in qualification testing of steam sterilizers after repair, guaranteeing optimal functionality post-maintenance.
Internal Chemical Indicators
Type 3 and Type 4 Internal Chemical Indicators
Type 3 indicators respond to specific critical variables, indicating exposure to a sterilization process at a predefined value of the chosen variable. On the other hand, Type 4 indicators react specifically to multiple critical variables. Type 4 indicators are frequently used for pack release in sterilization departments. These chemical indicators undergo a color change when exposed to a predetermined temperature for a specified duration during steam sterilization.
Type 5 Chemical Indicators (Integrating Indicators)
Intergating indicators respond to all critical variables in the sterilization process. Integrators have stated values meeting or surpassing the performance requirements set by ANSI/AAMI/ISO 11138 for Biological Indicators. The stated values determine the indicator’s reaction rate to temperature changes. Type 5 Integrators are also known as “moving front indicators.” Type 5 integrators contain ink that migrates across the indicator when exposed to conditions corresponding to their stated values. This migration visually confirms successful sterilization, offering a reliable and efficient means of monitoring the entire sterilization process.
Type 6 Chemical Indicators (Emulating Indicators)
Type 6 indicators, also known as cycle verification indicators, respond to critical variables specific to defined sterilization cycles. Their uniqueness lies in their cycle-specific nature, ensuring accuracy and precision. These indicators feature color-changing ink that reacts when exposed to the correct stated values during a sterilization cycle. This ink transformation confirms the successful exposure to specified conditions, instilling confidence in the effectiveness of the sterilization process. Type 6 indicators are used for pack and load monitoring.
How to use Chemical Indicators
During prep & pack place either Type 4 or Type 5 indicators inside of each package or tray. Be sure to place an indicator such that:
- An indicator is visible when the pack is opened in the OR
- There are indicators in the most challenging areas for sterilant penetration.
Wrap or close the package or tray using a Type 1 External chemical indicator on the outside of the package.
In the sterilization load, include a test pack or process challenge device containing Type 5 or Type 6 chemical indicators. If the load contains implants, add a biological indicator to the test pack. After completing the sterilization cycle, promptly examine both external and internal indicators. Check for visible color changes or ink migration on the chemical indicators and compare their responses to the manufacturer’s instruction for use for confirmation.
Remember to follow all specific guidelines provided by the indicator manufacturer and maintain proper record-keeping to comply with quality assurance protocols. By using Internal Chemical Indicators in this manner, healthcare facilities and other industries can ensure the safety and efficacy of their sterilization processes.
Understanding the different types of chemical indicators is crucial for ensuring the effectiveness and reliability of steam sterilization practices. By employing appropriate chemical indicators, healthcare professionals can maintain the highest standards of sterilization and patient safety. Stay informed, choose the right chemical indicators for your needs, and promote the excellence of your sterilization processes.
*In 2014, ISO committees made the decision to change the classification of chemical indicators into Classes with the use of Types.