Sterilization or Disinfection? It’s time to Modernize the Spaulding Classification System!

In 1968, Dr. Earle Spaulding classified medical devices into three categories based on device usage and body contact.  What we currently know as the Spaulding system, classifies devices as critical (presenting a high risk), semi-critical and non-critical (presenting a low risk) depending on the infection risk involved. The system also classifies the appropriate level of processing (sterilization or disinfection) necessary based on the criticality of the device. This Spaulding classification system has been used by infection preventionists and other healthcare providers for the last half a century.  Nevertheless, today, we have more knowledge regarding microbiology, microorganisms have also adapted to be more resistant, and devices have become increasingly complicated making them more difficult to reprocess, for that reason, some professionals feel it is high time to modernize the Spalding classification system.

The current Spaulding classification states devices that enter sterile tissue or the vascular system should be considered critical items and therefore be sterilized, eliminating all possible microbial growth. Devices that only come in contact with nonintact skin or mucous membranes such as flexible endoscopes are considered semicritical items. In 1968  Spaulding recommended those semicritical items also be processed by sterilization, or at a minimum, by high-level disinfection (HLD) which we know is designed to eliminate most, but not all, microorganisms. We know that HLD may not kill some highly resistant spores.

Currently, most healthcare facilities process items classified, as semicritical items via HLD (the minimum in the Spaulding system) and not sterilization, which is the preferred method.  Unfortunately, there are obstacles with some devices that will not allow the preferred processing method such as the design of some devices, manufacturer’s instructions for use  (IFU) not including current sterilization options, limitation on the number of devices as well as scheduling concerns.

Mucous membranes are a protective barrier to most bacterial spores, but not to organisms such as tubercle bacilli and viruses.  There is new clinical evidence that for at least some of these micro-organisms have biocide resistance and can lead to infection outbreaks due to unforeseen disinfection failure.  Therefore, professionals are now challenging the current Spaulding classification system.  In 2015 Dr. William Rutala proposed a modification to the Spaulding system at an FDA organized Endoscope Devices Panel.  He proposed that complex devices that secondarily enter sterile tissue or the vascular system, such as bronchoscopes, cystoscopes, or duodenoscopes be considered critical items and processed only by sterilization.

As a professional, I have always had concerns with HLD because these items are not protected from environmental or other contamination like packaged items undergoing sterilization, so they are most likely not at a high-level of disinfection when they get used on the patient.

On September 11th, 2017 AAMI conducted and Endoscope Sterilization Stakeholders meeting.  I was privileged to be one of the over 40 attendees at that meeting. Evidence indicating that sterilization is a superior method to high-level disinfection (HLD) for the reprocessing of endoscopes was reported by William Rutala, MS, MPH, PhD, Cori L. Ofstead, MSPH, and Michelle Alfa Ph.D., FCCM.

The stakeholders in attendance agreed that the move away from HLD to sterilization of endoscopes is a heavily nuanced issue and something that would need to happen gradually.

We must remember one very important part of any reprocessing and that is verification of the cleaning process, we know that if an item is not clean it can’t be sterilized or HLD!


  1. Central Service Technical Manual, Eighth ed. 2016, IAHCSMM, Chicago, IL
  2. Guidelines for Processing Flexible Endoscopes. In: Guidelines for Perioperative Practices. Denver, CO: AORN, Inc; 2016
  3. McDonnell G, Burke P. Disinfection: is it time to reconsider Spaulding? available at:, accessed 8/13/2017
  4. Strong Evidence for Sterilization of Endoscopes Presented at Stakeholder Meeting. Posted September 13, 2017 AAMI News and Views. Accessed 10/6/2017. Available at: