ANSI/AAMI ST108:2023— Water for Processing Medical Devices
Healthcare facilities decontaminate and sterilize reusable medical devices numerous times prior to use. The reprocessing of medical devices includes several processes, and water quality plays a crucial role, particularly in cleaning and steam sterilization. The water used is required to have certain characteristics, meeting specific quality standards, to assure the effectiveness of the processes. ANSI/AAMI ST108:2023— Water for the processing of medical devices outlines the required water characteristics for different stages of medical device reprocessing.
Why Is Water Quality Important in Medical Device Processing?
Rather than using untreated tap water, quality water is used daily to clean, disinfect, and sterilize millions of medical devices. Water quality is important in all stages of medical device processing because it can impact patient health (cause fevers, inflammations, infections, and other complications), device functionality, and manufacturing performance. Poor water quality can damage medical devices by causing staining, corrosion, pitting, malfunction, blocked lumens, reduces mobility of moving parts, and discoloration. In other words, using quality water for medical device processing improves cleaning chemistry effectiveness, reduces corrosion/damage, and improves steam quality for sterilization.
ANSI/AAMI ST108:2023 notes that water can be treated by a variety of methods that yield different levels of water quality. For example, gram-negative bacteria and nontuberculous mycobacteria can grow in water regardless of treatment process. As such, it is essential to closely monitor water systems quality in order to reduce variability of processing conditions and effectiveness of cleaning and disinfection processes as well as reduce the potential of microbial proliferation. ANSI/AAMI ST108:2023 defines multiple levels of water quality and steam purity suitable for medical device processing.
What Is ANSI/AAMI ST108?
ANSI/AAMI ST108:2023 covers the selection and maintenance of effective water quality suitable for processing medical devices. Specifically, the American National Standard covers the quality of the water delivered to the point-of-use and used in medical device processing (cleaning, rinsing, disinfection and sterilization). ANSI/AAMI ST108:2023 defines water types based on the qualities possessed and where it will be used:
- Responsibility for the water management program
- Importance of water quality
- Adverse effects of water impurities on medical device processing
- Categories and requirements of water quality for medical device processing
- Selection of water of the appropriate quality
- Purity requirements of water used to generate steam
- Effective water treatment and qualification
- Considerations for ongoing maintenance, monitoring, and quality improvement of the water treatment system
- Troubleshooting water quality issues
The standard also provides guidelines for selecting the water quality necessary for the processing of categories of medical devices and addresses water treatment equipment, water distribution and storage, quality control procedures for monitoring water quality, strategies for bacterial control, and environmental and personnel considerations.
Categories of Water Quality
ANSI/AAMI ST108:2023 establishes three categories of water quality important for medical device processing.
- Utility Water: water as it comes from the tap that can require further treatment at the facility to achieve water. This water is mainly used for flushing, washing, and intermediate rinsing (e.g., rinsing between cleaning and disinfection).
- Critical Water: water that generally requires extensive treatment by a multi-step process that can include a pretreatment, does include primary treatment (e.g., RO and/or DI), storage, distribution, and can include final treatment to provide a level of assurance that microorganisms and inorganic and organic material are removed from the water. This water is used for final rinsing or steam generation.
- Steam: vaporized water that is produced by a centralized boiler or a generator/heat exchanger near the sterilizer.
ANSI/AAMI ST108:2023— Water for the processing of medical devices is available on the ANSI Webstore and in the ANSI/AAMI ST108 / ANSI/AAMI ST79 – Water, Steam and Sterilization Set.
