January 7, 2013 (updated July 28, 2015) — A nurse asked, “I am reading conflicting reports about a stored flexible endoscope’s shelf life. For how long can a gastrointestinal (GI) endoscope be safely stored without requiring reprocessing before its reuse?”


A flexible endoscope may feature several complex internal channels, including, for example, a working  channel. Some types and models of endoscopes may also feature a narrow elevator-wire channel.

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Like a long drinking straw, these channels can retain or trap rinse water, which, if contaminated with microorganisms, can pose an increased risk of healthcare-associated infections during flexible endoscopy.[1-7]

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As important as cleaning and high-level disinfection, proper drying and storage of the endoscope are crucial to remove remaining rinse water and prevent the growth of opportunistic microorganisms within its internal channels.[1-6]

Indeed, improperly dried and stored flexible endoscopes—such as “ERCP” endoscopes and bronchoscopes—have been directly linked to patient morbidity and mortality.[1-7]

How is drying achieved?

Drying is typically achieved by manually flushing each of the endoscope’s internal channels with 70% (isopropyl) alcohol, followed by forced or compressed air.[1,2] (Refer to the endoscope manufacturer’s instructions for the volume of 70% alcohol required to flush each channel.)

Similarly, the endoscope’s exterior may be dried by wiping its surfaces with a clean or sterile gauze pad moistened with 70% alcohol.

By reducing the surface tension of water and aiding its evaporation, 70% alcohol facilitates the drying of the endoscope’s internal channels (and external surfaces).[1]

Methods to  verify whether the endoscope was adequately dried may include visual examination of the endoscope’s distal tip for water droplets, or placing a clean piece of tissue paper underneath the hanging endoscope’s distal tip during storage and observing the paper for water spotting.

When is drying necessary?

Endoscope reprocessing guidelines recommend drying the endoscope at the end of the day, before its storage.[1,3,7,8] Adhering to the long-standing infection-control principle that water or moisture on an instrument’s surfaces (or wrapping) poses an increased risk of contamination, some guidelines, however, also prudently recommend drying the endoscope between patient procedures, to ensure the clinical use of a dry instrument.[1,3,7,9]

As Muscarella has published,[9] few medical practices violate infection control principles more noticeably and pose more of a risk of opportunistic infections than, for example, the introduction of a bronchoscope—just reprocessed and still wet with rinse water—into a patient’s lungs. (Some guidelines and product labeling have confusingly endorsed this practice.)[7,8]


Endoscope storage

In addition to drying, endoscope reprocessing guidelines emphasize the importance of proper storage, recommending, for example, that the reprocessed and dried endoscope be vertically hung in a dry, clean, and well ventilated area or storage cabinet.[1]

These guidelines further recommend that the endoscope’s valves (e.g., suction, air/ water) and other detachable components be removed, to prevent the endoscope’s internal channels from retaining water, which could become contaminated with microorganisms and pose an increased risk of healthcare-acquired infection.[1]

Storage time

The number of days that studies suggest a gastrointestinal (GI) endoscope can be safely stored is not well-defined.

Concerned about the potential for microbial contamination and growth within the endoscope’s internal channels during storage, some guidelines recommend that every endoscope be reprocessed (again) just prior to reuse.[3,5,7,8]

Others, however, disavow this practice, noting that published data, although limited, suggest instead that the endoscope can be safely stored for 1 day[2,3,5,7] or 14 days.[6]

Indeed, some guidelines place no specific limit on the number of days that an endoscope can be safely stored.[1,3]

Concluding that insufficient data are available to require that a properly stored endoscope be reprocessed (again) prior to its reuse (or after a certain number of days), these latter guidelines—having adopted an event-related (as opposed to a time-related) paradigm—assert that the endoscope can be stored indefinitely—provided, however, that the endoscope was reprocessed and dried prior to storage in strict accordance with the instructions of published  infection control guidelines.[1,4,10]

Some guidelines and studies suggest that gastrointestinal (GI) endoscopes can be safely stored for 1 day[2,3,5,7] or 14 days.

Quality Reviews and Reports for Hospitals, Manufacturers, Patients:  Click here to read about Dr. Muscarella’s expertise and legal assessments of the causes of healthcare-associated infections, including “superbug” outbreaks linked to contaminated GI endoscopes and other reusable medical equipment.

Published studies

While published data are scant, Pineau et al. (2008)[2] suggest that colonoscopes stored for 2 to 3 days in a specific manufacturer’s environmentally-controlled drying cabinet do not require reprocessing before reuse.

Two other studies suggest that ERCP endoscopes(6) and colonoscopes[4,6] can be safely stored for 7 days,[4] or as long as two weeks.[6]

Similarly, Rejchrt et al. (2004)[10] reported that lower and upper GI endoscopes, including ERCP endoscopes, can be safely stored for as many as 5 days, though, as with some other studies,6 the ERCP endoscope’s elevator-wire channel—which when improperly reprocessed and dried has been directly linked to disease transmission[7]—was not studied.

[Remember to refer to Dr. Muscarella’s more detailed article on this topic, which is available by clicking here.  This more detailed article provides the tables (i.e., Table 1 and Table 2) that are referenced in this article.]

Osborne et al. (2007)[5] reported that properly reprocessed, dried, and stored endoscopes may be safely stored overnight and possibly for 5 days or longer.[5]

Click here to read Dr. Muscarella related article: “Investigation and Prevention of Bacterial Outbreaks during Endoscopic Retrograde Cholangiopancreatography (ERCP).


Reports suggest that endoscope-drying and storage practices, like cleaning and high-level disinfection, may vary considerably from one facility to another.[4,12]

Moreover, the data to support claims that a GI endoscope can be safely stored for a specific period of time (e.g., 3 hours; or 2-3, 5 or 7 days) without requiring reprocessing before its reuse are limited, if not at variance.[3]

More research is necessary to determine the “safe” shelf life of different types and models of flexible endoscopes, including not only colonoscopes but also ERCP endoscopes and bronchoscopes.

Read Dr. Muscarella’s article “Joint Commission and the Reprocessing and Storage of Laryngoscope Blades” by clicking here.

The following recommendations provide guidance to reduce the risk of disease transmission:

1.  As part of the reprocessing protocol, dry the endoscope’s internal channels and exterior using 70% alcohol in accordance with published guidelines.[1,15]

  • Perform this step between patient procedures and before storage, no matter whether manually reprocessing the endoscope or using an automated endoscope reprocessor (AER); or whether using sterile, “sterile” filtered, bacteria-free, or tap water for rinsing.[1]

2.  After drying it, store the endoscope in accordance with published guidelines.[1,15,16]

  • For example, hang the endoscope vertically in a clean, dry, well-ventilated area or storage   cabinet with the endoscope’s valves, biopsy cap, and other detachable components removed, to facilitate drying.[1,15]

3.  Establish a quality assurance program that (see: the box article in the right-hand column of this page):

(a) ensures that the endoscope removed from storage was properly reprocessed (and dried) prior to storage;[15]

(b) establishes that the environment or cabinet in which the endoscope was stored is monitored and controlled, to promote drying and prevent the growth of microorganisms within the endoscope’s internal channels; and

(c) documents the number of days each flexible endoscope, identified by its model and serial number, has been in storage (this practice would not be necessary if the medical facility reprocesses every endoscope before its reuse).

4.  Medical facilities with a quality assurance program in place (see: recommendation #3, above) may consider storing upper and lower GI endoscopes (with the exception of ERCP endoscopes; see: recommendation #7, below) for as many as 7 days, without having to reprocess the endoscope before its reuse.

  • Whether this recommendation—which is based on limited data and may be revised as additional data are published—can be soundly applied to other types of flexible endoscopes, such as cystoscopes, is unclear.
  • Alternatively, in compliance with one published guideline,[11] medical facilities may consider reprocessing before its reuse any flexible endoscope stored for more than 5 days.

5.  Examine each endoscope removed from storage prior to its use. Remove from service any endoscope identified to be damaged or otherwise unsafe for clinical use.

6.  Reprocess a stored endoscope before its reuse if:

(a) the facility does not have in place a quality assurance program (see: recommendation #3, above) that ensures the endoscope was reprocessed, dried, and stored in   accordance with published guidelines;[1,15-19]

(b) the facility’s quality assurance program is imperfect and the endoscope is removed from storage and identified by staff to be contaminated or to have been improperly   reprocessed, dried, or stored—for example:

(i) the endoscope is observed to be wet;

(ii) the endoscope’s distal tip is touching the ground;

(iii) the endoscope’s valves had not been removed;

(iv) the endoscope had been stored in an AER, automated “sterilizing” processor,[4] or pillow or carrying case;[16]

(v) the endoscope had been used during off hours and was not reprocessed by trained staff members prior to being placed back into storage; or

(c) the facility’s rinse water contains significant numbers of opportunistic microorganisms.[17]

7.  Consider reprocessing ERCP endoscopes and bronchoscope (and, possibly, enteroscopes) before their reuse, whether or not an adequate quality assurance program is in place.[29-31] (Published data in support of this recommendation are admittedly limited, though not lacking.)

Note: If you are a paying subscriber, email Dr. Muscarella to receive a free copy of the complete version of this article, in PDF format.

References to this article are available by clicking here.

Article by: Lawrence F Muscarella, PhD; posted 1-7-2013; updated 7-28-2015, Rev A.

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