What’s new in ANSI/AAMI ST91 latest update?

Dec. 22, 2021


 “I have heard that ANSI/AAMI ST91 has been approved. If that is true, what are some of the major changes we should be aware of?”


 I have been told it is ready for distribution sometime this month. As you know, there are hundreds of changes to the commentary. Some are just editorial, while others are technical. Here’s my Top 10 list of things to know about the new ST91.

  1. Precleaning renamed “Point of Use Treatment”: There is also now a recommendation to note the time when point of use treatment is conducted and convey that information to the processing staff so that they know whether or not to follow the delayed reprocessing procedure.
  2. Leak testing procedure has been changed to 60 seconds of observation instead of 30 seconds: There is now a recommendation to test the leak test units for pressure output every day the unit is used.
  3. Added a designation of “high-risk” endoscopes: The standard contains different guidance for processing high-risk versus non-high-risk endoscopes.
  4. Cleaning verification testing intervals have changed: ST91 now requires cleaning verification on all high-risk endoscopes and a statistically significant portion of non-high-risk endoscopes. The document walks you through how to figure that out in an annex.
  5. Strengthened guidelines around enhanced visual inspection: The standard now recommends the use of lighted magnification.
  6. Borescope inspection is now recommended at a periodic interval determined by the facility.
  7. Manual disinfection is no longer recommended due to the variability/inconsistency personnel responsible for the process: That’s a big one!
  8. ST91 strengthened wording on which scopes should be sterilized and which may be high-level disinfected: All endoscopes should be sterilized (if possible), but if not possible, then we resort to high-level disinfection. Endoscopes used in a critical application—meaning used in a sterile area of the body—must be sterilized.
  9. All endoscopes are now required to be completely dried (both externally and internally) before reuse, even though they were run through an AER: This does not matter whether the endoscope is going into the storage cabinet or back to immediate reuse; all scopes should be subjected to a compressed air-drying cycle of 10 minutes or placed into a drying cabinet to dry internally. This will add time to the processing cycle.
  10. Endoscopes should be handled with new, clean gloves (at all times): Perform hand hygiene before donning and after doffing gloves.

ST91 is a document that involved and reflects the collective expertise of a committee of healthcare professionals and industrial representatives.

I want to thank the AAMI co-chairs: user co-chairs Nancy Chopin and her successor Garland Grisby and industry co-chair Mary Ann Drosnock (whose term just ended upon ST91’s completion). Thank you for your hard work and dedication through the development of the new ST91 document.

As with any standard document (especially this one), my suggestion is to order your own copy from AAMI at www.aami.org to read the complete document. You asked for my thoughts about the changes in ANSI/AAMI ST91. If you want an official interpretation of any AAMI standards and recommended practices, you must make it in writing to the AAMI Vice President, Standards Policy and Programs. Good luck in implementing ANSI/AAMI ST91 at your facility. 

Original photo courtesy Bayhealth SPD, HPN's 2021 SPD of the Year, with affects added by generative AI.
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