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The Guideline for Processing Flexible Endoscopes was approved by the AORN Guidelines Advisory Board and became effective February 1, 2016. It was presented as a proposed guideline for comments by members and others. The recommendations in the guideline are intended to be achievable and represent what is believed to be an optimal level of practice. Policies and procedures will reflect variations in practice settings and/or clinical situations that determine the degree to which the guideline can be implemented. AORN recognizes the many diverse settings in which perioperative nurses practice; therefore, this guideline is adaptable to all areas where operative or other invasive procedures may be performed.


This document provides guidance to perioperative, endoscopy, and sterile processing personnel for processing all types of reusable flexible endoscopes and accessories. Recommendations are provided for design and construction of the endoscopy suite as well as for controlling and maintaining the environment to support processing activities. Guidance is provided for maintaining records of processing for traceability and for quality assurance measures related to processing flexible endoscopes and accessories.

Patients have a right to undergo endoscopic procedures in a safe, clean environment where personnel adhere to consistent, evidence-based practices for processing every flexible endoscope every time care is provided. It is essential that the risk of patient-to-patient transmission of infection via flexible endoscopes be minimized as much as is reasonably possible.

Infections related to endoscopy procedures may be caused by endogenous microorganisms that colonize the mucosal surfaces of the gastrointestinal or respiratory tract and gain access to the bloodstream or other sterile tissues as a consequence of the procedure.1  Endogenous infections include infections such as cholangitis that may occur after endoscopic procedures of the biliary tract or pneumonia that may occur after endoscopic procedures of the respiratory tract.1 

Infections related to endoscopy procedures may also be caused by exogenous microorganisms that are transmitted from previous patients or from the inanimate environment by contaminated endoscopes or accessories.1  The US Food and Drug Administration (FDA) has identified two recurrent themes as contributing to persistent bronchoscope contamination and transmission of exogenous infection:

  • a failure to meticulously follow the manufacturer’s written instructions for processing and

  • the continued use of bronchoscopes despite issues with integrity, maintenance, and mechanical problems.2 

If flexible endoscopes are not correctly processed, exposure to body fluids and tissue remnants from previous patients may result in the transmission of pathogens to large numbers of subsequent patients.3  In a systematic search of the literature to clarify the epidemiology of Klebsiella species in endoscopy-associated outbreaks, Gastmeier and Vonberg4  found that insufficient processing was the main reason for subsequent pathogen transmission. The authors concluded that strict adherence to guidelines for processing flexible endoscopes in combination with alertness to the potential for pathogen transmission after endoscopy procedures was required, and that additional studies were needed to determine the true risk of pathogen transmission via flexible endoscopes.

Because of the many different types of flexible endoscopes and the differences in flexible endoscope construction, not all steps discussed in this guideline (eg, leak testing) will apply to all endoscopes; however, some steps (eg, manual cleaning) will apply to all flexible endoscopes. The European Society of Gastrointestinal Endoscopy (ESGE) has proposed a classification of endoscope families5  based on similar characteristics, including the number, construction, and purpose of the different endoscope channels and their clinical applications.

  • Group 1 endoscopes are typically intended for use in the gastrointestinal tract. This group includes endoscopes that have air/water channels, have an instrument/suction channel, and may have an additional instrument or waterjet channel. Examples of Group 1 endoscopes are gastroscopes, colonoscopes, and duodenoscopes with an encapsulated elevator channel.

  • Group 2 endoscopes are also intended for use in the gastrointestinal tract. This group includes endoscopes that have air/water channels, have an instrument/suction channel, and may have an additional instrument channel. Group 2 endoscopes also may have an elevator channel and up to two control channels for balloon functions. Examples of Group 2 endoscopes are duodenoscopes with an open elevator channel, echoendoscopes used for endoscopic ultrasound, and enteroscopes.

  • Group 3 endoscopes are used in bronchoscopy, otorhinolaryngology applications, gynecology, and urology. This group includes endoscopes with only one channel system for biopsy, irrigation, and suction or endoscopes without any channel. Examples of Group 3 endoscopes are bronchoscopes, cystoscopes, laryngoscopes, and nasendoscopes.

In addition to following the guidance provided in this document, it is critically important for individuals who are responsible for processing Group 1, 2, or 3 flexible endoscopes to follow the manufacturer’s instructions for use (IFU) and the IFU for all products and equipment used for processing flexible endoscopes. Processing flexible endoscopes is a complex cycle of multiple steps that includes point-of-use precleaning, transporting, leak testing, cleaning, inspecting, high-level disinfection (HLD) or liquid chemical sterilization, packaging and sterilization, storage, and use (Figure 1).

Figure 1
Roman numerals indicate the recommendation number where detailed guidance is provided.

Roman numerals indicate the recommendation number where detailed guidance is provided.

The complex design of flexible endoscopes increases the efficiency and effectiveness of endoscopic procedures; however, it creates enormous challenges for effective processing.3  Some parts of the endoscope may be difficult or impossible to access, and effective cleaning of all areas of flexible duodenoscopes may not be possible.6 

Although single-use devices may meet the quality of reusable endoscopic devices and may provide an option for reducing the risk for transmission of infection,7-10  a discussion of the potential benefits of single-use flexible endoscopes is outside the scope of this guideline. The use of airborne, contact, or droplet precautions, the various chemicals used as high-level disinfectants or liquid chemical sterilants, the methods used for HLD or low-temperature sterilization, the methods for determining water quality used for processing flexible endoscopes and accessories, the protocols for microbiological surveillance of flexible endoscopes, the management of processing failures, sharps and medication safety, and the ergonomic injuries associated with the endoscopy environment are also outside of the scope of this guideline.

A full discussion of the design and construction of endoscopy suites in hospitals and outpatient facilities, the design of ventilation systems for controlling personnel exposure limits to chemicals used in the endoscopy suite, and the performance and use requirements for eyewash and shower equipment are outside of the scope of this document. However, because the design of the endoscopy suite and the procedures performed in the facility affect the processing of flexible endoscopes, some recommendations have been provided relative to procedure rooms and other elements of the endoscopy suite.

Evidence Review

A medical librarian conducted a systematic search of the databases Ovid MEDLINE®, EBSCO CINAHL®, and Scopus® as well as of the Ovid Cochrane Database of Systematic Reviews. Search results were limited to literature published in English from 1994 through 2014. At the time of the initial search, the librarian established weekly alerts on the search topics and until October 2015, presented relevant results to the lead author. The author and the librarian also identified relevant guidelines and guidance from government agencies, professional organizations, and standards-setting bodies. Finally, during the development of this guideline, the author requested supplementary searches for topics not included in the original search as well as articles and other sources that were discovered during the evidence-appraisal process.

Search terms included the subject headings endoscopes, disinfection, decontamination, sterilization, disinfectants, detergents, biofilms, infection control, cross-infection, equipment contamination, occupational exposure, protective clothing, and hypersensitivity. Subject headings and key words for specific types of endoscopes, bacteria, disinfectants, and protective devices also were included, as were headings and terms related to the concepts of endoscope storage, methods of reprocessing, disinfection monitoring, infection transmission, disposable and reusable equipment, occupational allergies and injuries, and air pollution and ventilation. Complete search strategies are available upon request.

Excluded were non-peer-reviewed or retracted publications and evidence specific to the mechanism of action or health hazards associated with specific high-level disinfectants or liquid chemical sterilants, rigid endoscopic instrumentation, endoscopic medical treatment protocols, techniques, patient management, or functional design of flexible endoscopes.

In total, 1,257 research and non-research sources of evidence were identified for possible inclusion, and of these, 418 were cited in the guideline (Figure 2).

Figure 2
Flow Diagram of Literature Search Results

Flow Diagram of Literature Search Results

Adapted from Moher D, Liberati A, Tetzlaff J, Atman DG; The PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(6):e1000097.

Articles identified by the search were provided to the lead author and an evidence appraiser. The lead author and the evidence appraiser reviewed and critically appraised each article using the AORN Research or Non-Research Evidence Appraisal Tools as appropriate. The literature was independently evaluated and appraised according to the strength and quality of the evidence. Each article was then assigned an appraisal score. The appraisal score is noted in brackets after each reference as applicable.

Each recommendation rating is based on a synthesis of the collective evidence, a benefit-harm assessment, and consideration of resource use. The strength of the recommendation was determined using the AORN Evidence Rating Model and the quality and consistency of the evidence supporting a recommendation. The recommendation strength rating is noted in brackets after each recommendation.

Note: The evidence summary table is available at

Editor’s note: MEDLINE is a registered trademark of the US National Library of Medicine’s Medical Literature Analysis and Retrieval System, Bethesda, MD. CINAHL, Cumulative Index to Nursing and Allied Health Literature, is a registered trademark of EBSCO Industries, Birmingham, AL. Scopus is a registered trademark of Elsevier B.V., Amsterdam, The Netherlands.

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