AAMI ST108 Testing Services for Reusable Medical Devices

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Pace® AAMI ST108 Testing Services

A leader in water testing services, Pace® provides a complete portfolio of water testing services for healthcare providers to ensure adherence to the latest AAMI ST108 water quality standards. Our water testing services cover both chemical and microbiological testing for all categories of water used to clean or disinfect reusable medical devices. In addition, we offer water management planning services to help healthcare facilities mitigate risks to patient safety from existing water systems.

What is AAMI ST108?

AAMI ST108:2023 is a water quality standard defined by the Association for the Advancement of Medical Instrumentation (AAMI). It defines the water quality necessary to safely process reusable medical devices, ensuring no harmful contaminants interfere with the function or safety of these devices.

AAMI ST108:2023 replaced AAMI TIR34:2014/(R)2021 in 2023. As an industry standard, compliance with AAMI ST108 is not required by law. However, adherence to the standard is considered a best practice for protecting patient safety and may be required by accreditation organizations, such as the Joint Commission.

Device Categories Under AAMI ST108

Under AAMI ST108, devices are categorized based on the risks they pose to patient safety. These categories are used to determine the quality of water necessary to appropriately process the devices.

Non-Critical

These devices are typically non-invasive, e.g., a blood pressure cuff, and rarely associated with disease.

Semi-Critical

Semi-critical reusable medical devices come in contact with intact mucosal membranes or nonintact skin, but do not usually penetrate the blood barrier. Examples include endotracheal and aspirator tubes. If not properly cleaned, they can be associated with disease, so are subject to a higher standard of processing.

Critical

Critical devices pose the highest risk of infection as they come into direct contact with the blood stream or other sterile fluid pathways. Examples include surgical devices and cardiac catheters.

Water Categories Tested Under AAMI ST108

Utility Water

AAMI ST108 defines utility water as the type of water that comes directly from the tap. It is suitable for various general cleaning tasks, such as flushing, washing, and rinsing medical devices. To ensure patient safety, utility water must meet specific chemical water quality criteria. Thus, this water may require further treatment depending on its intended use.

Critical Water

Critical Water is primarily used for final rinses of critical and semi-critical medical devices after chemical sterilization. This type of water is treated to a higher standard for chemical constituents and must be tested for bacteria and endotoxins.

Steam

Steam is typically used in the last stage of processing reusable medical devices for sterilization. The condensate is tested and must typically meet the same quality criteria as Critical Water.

AAMI ST108 Water Testing Requirements

Under AAMI ST108, water testing requirements are defined by the type of water and how it will be used.

Performance Qualification

Utility water, critical water, and steam systems must undergo an initial performance qualification that looks at both chemical and biological contaminants. Water quality criteria include pH, conductivity, total alkalinity, total hardness, bacteria (HPC), and endotoxin (LAL). (Endotoxin testing is not required for utility water or steam. In addition, bacteria testing is not required for steam.)

Utility water and steam are also not required to undergo testing for total organic carbon (TOC). Otherwise, all three water categories must be initially tested for the following chemical compounds:

Total Organic Carbon (TOC)
Aluminum
Chloride
Copper
Iron
Manganese
Nitrate
Phosphate
Silicate
Sulfate
Zinc

Routine Water Quality Testing for Water Generation

“Water Generation” refers to the water systems used to produce the water used to clean and/or sterilize reusable medical devices. These systems must undergo routine testing based on the intended use of the water generated. Note that steam is not considered in this category of routine testing. In addition, routine testing for individual ions and TOC are not required.

Utility Water - Must undergo quarterly testing for pH, conductivity, total alkalinity, and total hardness.

Critical Water – Must undergo monthly testing for pH, total alkalinity, total hardness, bacteria (HPC), and endotoxins (LAL). Critical Water must also undergo daily testing for conductivity, though this can be performed using an inline or in-tank meter.

Routine Quality Testing for Point of Use Water

Water at the point of use must also undergo routine testing. Once again, what gets tested and at what frequency is determined by how the water us being used.

Utility Water – Must undergo quarterly testing for pH, conductivity, total alkalinity, total hardness, and bacteria (HPC).

Critical Water - Must undergo monthly testing for pH, conductivity, total alkalinity, total hardness, bacteria (HPC), and endotoxins (LAL).

Steam – Must undergo quarterly testing for pH, conductivity, total alkalinity, and total hardness.

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Water Management Planning

Protecting patient health and safety starts with thorough water management planning. Our full-service water management plans have helped many healthcare organizations comply with ASHRAE 188 and follow all Joint Commission and CMS recommendations. Water management planning for water used in medical device reprocessing is also a key step to successfully managing risk. We provide auditing services for your existing water management plans to ensure adherence to the latest rules, best practices, and scientific methods for waterborne pathogens testing and risk mitigation.

Put Pace® on Your AAMI ST108 Team

AAMI recommends including water quality management professionals on your ST108-compliance team. Pace^® has been providing water quality testing services and guidance to healthcare organizations and other professionals for more than three decades. We are experts in testing for organic and inorganic contaminants as well as waterborne pathogens in potable and non-potable water. Over the years, our experts have helped numerous facilities adhere to such critical standards as ASHRAE 188 and those recommended by the Joint Commission, the Centers for Medicare & Medicaid Services (CMS), and AAMI.