Although rare, numerous outbreaks of disease transmission to patients have been documented and traced back to contaminated endoscopes. In some cases, lapses in proper cleaning and disinfection were discovered. But in other cases, no lapse was ever found.
Persistent contamination concerns are fueling an ongoing discussion among researchers and regulators about whether the usual disinfection procedures used with endoscopes are adequate. Some organizations are raising questions about whether endoscopes need to be sterilized.
Either way, whether an endoscope is disinfected or sterilized, effective manual cleaning before disinfection or sterilization remains what many experts call “the most important step” in processing flexible endoscopes.
But how do you know if an endoscope has been properly cleaned?
We’ve compiled an easy-to-use reference about endoscope cleaning and cleaning verification tests for infection preventionists, for managers, and for staff who clean endoscopes.
Endoscopes are flexible or semi-rigid devices that enable visualizing a hollow organ or body cavity for medical assessment and diagnosis, tissue biopsy, secretion collection, or administering treatment. Some endoscopes also have cutting tools used to perform surgery.
In addition to lights and cameras, some endoscopes have multiple channels, levers and moving parts that can make them very difficult to clean and disinfect properly between patients.
Endoscope cleaning recommendations, as well as disinfection or sterilization guidance, typically follows the endoscope manufacturer’s instructions. Endoscopes and accessories receive at least high-level disinfection, or HLD, based upon their Spaulding classification.
The Spaulding system has three classifications for devices to be reprocessed: critical, semicritical or noncritical, depending on their risk of transmitting infections.
Critical devices have a high risk of transmitting infection because they come in contact with normally sterile tissues or body cavities, including the vascular system. Critical devices include surgical instruments, biopsy forceps, urinary and vascular catheters, and implants. These items must be sterilized.
Semicritical devices have a moderate risk of transmitting infections because they come in contact with mucous membranes or non-intact skin. Semicritical devices include respiratory therapy and anesthesia equipment, laryngoscope blades, vaginal ultrasound probes and specula, and many endoscopes.
These items must receive a minimum of high-level disinfection (HLD), where all microbial life is destroyed except for a small number of bacterial spores. Sterilization is preferred for these devices when practical.
Noncritical devices have a low risk of transmitting infections because they contact intact skin. Noncritical devices include things like blood pressure cuffs, crutches, bedpans, and environmental surfaces like bed rails. Noncritical devices must receive low-level or intermediate-level disinfection, depending on their intended use.
Spaulding classifications are currently under review by numerous international and professional organizations.
Endoscopes should receive at least high-level disinfection (HLD) after thorough cleaning, according to current recommendations.
Subjecting endoscopes to HLD or sterilization if they haven’t been properly cleaned, however, is ineffective, because the disinfectant may not penetrate the biofilms and organic residues that can support microbial life. These must be removed by proper manual cleaning.
The Association of periOperative Registered Nurses (AORN) recommends cleaning verification testing to check whether cleaning has been effective before proceeding. For any cleaning verification test, a cleanliness benchmark needs to be established and rapid, easy-to-perform methods need to show whether that benchmark has been met.
The Reprocessing Recommendations section of this website explores these tests and discussions about proper cleaning. We’ll also be publishing articles about various kits currently on the market:
Many people think that some endoscopes should be considered critical devices, subject to sterilization. This is because endoscopes often contact the bloodstream or sterile tissue via non-sterile mucous membranes. Some tools, such as those used for biopsy procedures, are sterilized and then passed through a non-sterile endoscope, causing some to wonder whether the tools remain sterile.
Unfortunately, the materials currently used to make reusable endoscopes render them unfit for traditional heat sterilization. Chemical and gas sterilization technologies exist but they are not feasible for every facility or every endoscope. Some of the technologies currently under discussion include ethylene oxide (EO), hydrogen peroxide (HP) gas or ozone for heat-sensitive objects, while using steam sterilization whenever possible.
The manufacturer’s instructions for HLD or sterilization must be meticulously followed; any sterilization method must be validated by the endoscope manufacturer.
In addition to changing recommendations, some companies are beginning to make sterile, single-use, endoscopes.
Some endoscopes have design features than can make them particularly difficult to clean.
The U.S. Food and Drug Administration, the U.S. Centers for Disease Control and Prevention and the Centers for Medicare and Medicaid Services have all issued alerts regarding the difficulty cleaning the “elevator” mechanism of side-viewing duodenoscopes, even when the manufacturer’s reprocessing instructions have been properly followed.
The elevator mechanism changes the angle of the tool exiting the accessory channel, allowing the instrument to access biliary and pancreatic ducts. During a procedure known as endoscopic retrograde cholangiopancreatography, or ERCP, the duodenoscope can be used to drain fluids that have been blocked from draining by tumors, gallstones or other conditions.
ERCP can be lifesaving and prevent the need for more invasive surgery. More than 500,000 ERCP procedures are performed each year in the U.S. Multiple outbreaks of the extremely drug-resistant infection known as Carbapenem-resistant Enterobacteriaceae (CRE) began in 2012 to be associated with duodenoscopes, especially those used for ERCP.
ERCP-related outbreaks of CRE and other multidrug-resistant organisms have been reported by at least eight major U.S. medical centers, and outbreaks have also occurred worldwide.
E. coli and Klebsiella bacteria are other kinds of CRE infections that have become resistant to antibiotics known as carbapenems. These are usually used as “drugs of last resort” for life-threatening bacterial infections. CRE infections in particular are known to be hard to treat and often fatal.
Endoscopes can transmit numerous bacterial infections and viral infections aside from CRE, but the deadly threat of CRE has raised the level of concern about endoscopes.
For a more detailed discussion on high-level disinfection of endoscopes, see the Reprocessing Recommendations section on this site. There can be multiple smaller steps within each of these steps, depending upon the endoscope model, but these are the main boxes to check.
Each step must be performed on each channel of the endoscope, even if that channel wasn’t used in the procedure. The manufacturer’s instructions must be followed meticulously, and the Centers for Medicare and Medicaid Services advises following professional guidance such as the Multisociety Guideline, which was updated in 2016.
1. Precleaning at the point of use
2. Leak testing
3. Manual cleaning
4. Rinse after cleaning
5. Visual inspection
6. High-level disinfection
7. Rinse after high-level disinfection
1. Center for Medicare and Medicaid Services, Center for Clinical Standards and Quality/Survey and Certification Group, April 3, 2015: ”Alert Related to Outbreaks of Carbapenem-Resistant Enterobacteriaceae (CRE) during gastrointestinal endoscopy, particularly Endoscopic Retrograde Cholangiopancreatography (ERCP)”
2. Petersen et al. “Multisociety guideline on reprocessing flexible GI endoscopes: 2016 update.” Gastrointestinal Endoscopy 2017: 85, No. 2, pp. 282–294.
3. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. William A. Rutala, Ph.D., M.P.H.1,2, David J. Weber, M.D., M.P.H.1,2, and the Healthcare Infection Control Practices Advisory Committee (HICPAC).
4. U.S. Centers for Disease Control and Prevention (CDC). “Interim Protocol for Healthcare Facilities Regarding Surveillance for Bacterial Contamination of Duodenoscopes after Reprocessing.” Version 3.11.15.
5. Association of periOperative Registered Nurses (AORN). “Guideline for Processing Flexible Endoscopes” in Guidelines for Perioperative Practice. Denver, CO, 2016: pp. 675-758.
6. Association for the Advancement of Medical Instrumentation (AAMI) with the American National Standards Institute Inc. (ANSI). “ANSI/AAMI ST91:2015: Flexible and semi-rigid endoscope processing in health care facilities.” Association for the Advancement of Medical Instrumentation. Arlington, VA, 2015.
7. The Joint Commission (TJC) with the Association for Professionals in Infection Control and Epidemiology (APIC). The APIC/JCR Infection Prevention and Control Workbook, 3rd ed. Oak Brook, IL, 2017.
8. The Healthcare Infection Control Practices Advisory Committee (HICPAC). “Essential Elements of a Reprocessing Program for Flexible Endoscopes—Recommendations of the Healthcare Infection Control Practices Advisory Committee.” July 2016.
9. U.S. Centers for Disease Control and Prevention (CDC). “CDC Statement: Los Angeles County/UCLA investigation of CRE transmission and duodenoscopes.” Last updated November 16, 2015.
10. FDA 2015 Materials of the Gastroenterology-Urology Devices Panel May 14–15, 2015: Meeting Materials Dr. William Rutala presentation.