ST91: Extensive Updates for Endoscope Cleaning, Patient Safety


By: Brian Stallard

March 3, 2022

Categories: AAMI News, Sterilization Professionals

Doctors prepare a hospital patient for endoscopy

After seven years, the standard for cleaning and storing a long list of medical devices, such as flexible bronchoscopes and various endoscopes, has been updated to reflect the consensus of industry, clinicians, and sterilization professionals from around the world. The improved guidance document, ANSI/AAMI ST91:2021, Flexible and semi-rigid endoscope processing in health care facilities, addresses new technologies as well as concerns about medical device cleanliness and patient safety.

“We really beefed it up,” said Mary Ann Drosnock, director of Clinical Affairs at Healthmark Industries and a member of AAMI’s Endoscope Reprocessing Working Group (ST-WG 84) since its inception.

“We wanted to make sure that everybody's voices were heard and that all comments were discussed and resolved properly,” she added. “There was no question afterwards. This guidance is about patient safety and we have the data baked in to support it.”

Drosnock was joined by Garland-Rhea Grisby, an endoscope service manager for Kaiser Permanente in Northern California, in co-chairing ST-WG 84 and leading the ST91 revision effort. According to the co-chairs, this updated standard is the fruit of the combined work of medical device manufacturers, sterilization professionals, academics, physicians, nurses, hospital accreditation organizations, and the US FDA and other government agencies.

Grisby added that oftentimes, it is the sterilization professionals who are pushing for more stringent regulations and requirements in the interest of safety, even if it means more work within their department.

“When they want to introduce change in their facility that can improve safety, they might get pushback from leadership because there are few guidelines out there that say what they should do or how to do it,” he explained. “That’s why they need this document to back up and outline what needs to be done.”

ANSI/AAMI ST91:2021 includes:

  • Classification for high-risk scopes, such as bronchoscopes and ureteroscopes
  • Updated guidance for drying of scopes, as well as proper storage and handling
  • Recommendations against manual disinfection
  • Guidance for testing water in automated endoscope re-processors (AERs) to avoid the final-rinse water re-contaminating the scopes
  • Guidance for determining the length of storage, or “hang time,” that a scope can withstand before needing to be reprocessed

A hospital sterilization professional in full PPE prepares medical instruments for cleaning.

A Change for Everyone

According to Drosnock and Grisby, the standard will always need periodic updates to ensure the state-of-the-art of sterile processing is keeping pace with changing technologies. However, an improved understanding of the sciences that drive sterility assurance are also important factors for identifying best practices.

“As an example, we now do not recommend that they disinfect scopes manually at all,” said Drosnock. “It used to be that you soaked the scope in a basin filled with disinfectant, and then you let it sit there. People thought ‘longer is better,’ but this creates fumes that are harmful to staff.”

She explained that this is a practice that is still widely seen in outpatient and office settings, “but we no longer recommend that in any setting,” after peer-reviewed studies showed the adverse impacts this practice may have on user health.

The standard, which is widely recognized as the state-of-the-art for hospital sterilization departments, has also been updated to account for outlier settings, such as surgery centers or physician offices. “This is really meant to be used in any healthcare setting that is reprocessing endoscopes,” said Drosnock.

What are the key areas of the document that IPs can focus on to ensure their facility is compliant with the new standard? Don’t miss:ST91:2021 Webinar

A Case for Change

“For some facilities, adopting this document is going to mean major changes and even major purchases,” she added.

However, the working group is confident that responsible health systems and facilities will not hesitate to adopt the changes in the interest of staff and patient safety. After all, the revised standard reflects and expands upon recommendations issued by the FDA this year in the interest of helping healthcare providers prevent infections caused by or related to reprocessed urological endoscopes.

And that’s no coincidence. The FDA’s representatives have been directly involved in the development of ST91, alongside numerous other stakeholders. In addition to accounting for regulatory concerns, the new standard comes with extensive appendices citing peer-reviewed research and data to support the requirements and recommendations of the document.

“We're not just throwing out statements just because we wanted people to do this,” said Grisby, adding that the document accounts for scientific discovery, patient safety data, and manufacturer instructions for use for medical devices.

Sterilization professionals “now have the fuel to be the spark for the change in their facility to implement more quality processes,” said Drosnock.

Interested in becoming a spark for change in the standards space? ST-WG 84 is always looking for more clinicians and sterilization professionals to represent their profession. Apply to join the AAMI working group at standards@aami.org.

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