AAMI Revises Steam Sterilization Standard

The Association for the Advancement of Medical Instrumentation (AAMI) will soon release a major update of its popular steam sterilization standard, ST79, to incorporate new information on risk analysis, chemical indicators, and other topics.

The AAMI Standards Board and the American National Standards Institute (ANSI) recently approved 26 changes and additions to ANSI/AAMI ST79, Comprehensive guide to steam sterilization and sterility assurance in healthcare facilities. The amendment is expected to be published in late July/early August. Prior purchasers of ST79 may download a free PDF of this amendment from www.aami.org.

The amendment is part of a continuous maintenance process for ST79, which initially resulted in a 2008 amendment.

“The focus of the continuous maintenance process is mainly on significant revisions that can be adopted and implemented more quickly,” says Judy Veale, AAMI standards coordinator.

ST79 now contains new information and guidance for chemical indicators, which are used to ensure that instruments are sterilized properly. Chemical indicators are divided into classes to suit different monitoring needs. Class 1, for example, indicates visually whether a load has been processed, and Class 5 monitors all critical parameters of sterilization.

Some changes to ST79 update descriptions of chemical indicators to correspond with a recently revised standard, ANSI/AAMI/ISO 11140-1:2005, Sterilization of health care products—Chemical Indicators—Part 1: General requirements.

AAMI’s Steam Sterilization Hospital Practices Working Group, which is responsible for authoring and updating ST79, included information on a new class of chemical indicator called a Class 6 Emulating Indicator, which is designed to react to all critical variables, such as time and temperature, of a sterilization cycle. “The working group has introduced the definition of Class 6 so people are aware it exists and is available,” Veale says. “The group has not developed consensus recommendations for how people should use this type of indicator.”

Other changes offer additional guidance on processing a sterilization failure. “The changes add a checklist to give sterilization service personnel more detailed recommendations on what to do when there is a positive biological indicator, or other indication of a sterilization failure,” Veale says.

The working group decided to add an entire section on risk analysis. “It was felt that there should be some information specifically on that subject as it relates to sterilization,” Veale says.

A risk analysis involves “looking at your processes and thinking ahead, such as what are your processes and what could go wrong,” says Cynthia Spry, an independent clinical consultant. “How do you plan to prevent something from going wrong?”

A risk analysis includes a risk assessment, which identifies the source, likelihood, and consequences of a sterilization failure. It also assesses the preparedness to manage a failure.

Risk management, which encompasses selecting and implementing plans to ensure that sterilization failures are controlled, and risk communication are also addressed in the new section.

Other additions to ST79 include:

-- New recommendations for assessing the efficacy of cleaning equipment

-- Revised recommendations for testing for rigid containers

-- Acceptance criteria for qualification testing of flash sterilization cycles

The Joint Commission also has updated its position on steam sterilization.