Drying is an essential step when reprocessing endoscopes. It helps preserve the pristine condition of the endoscope following the automated endoscope reprocessor’s cycle. Drying is recognised as a critical step of the process; however, there’s little clarity on how to repeatedly produce a dry, safe endoscope. [1-3]

The act of drying is a process. The goal is to enhance patient safety by removing all measurable moisture from the endoscope, reducing the possibility of microbial cross-contamination.

However, it can get tricky because multiple factors can affect the amount of time it takes to dry an endoscope. The combination of air (air volume, air pressure, air quality, and the air’s moisture content) and individual endoscope specifications (lumen length and diameter, and number of lumens) all must be considered when instituting an endoscope drying protocol. Setting an arbitrary minimum time to dry without control of all these factors will not deliver a consistently dry endoscope. A proposed “dry time” of 10 minutes only starts the drying process but hasn’t been shown to complete it universally. [4]

Incomplete drying practices limit the efficacy of reprocessing, rather than strengthen its benefits. It’s time we look in the mirror as an industry and be honest about the potential danger in established perceptions.

Drying’s Role in Infection Prevention

Endoscopes become highly contaminated during procedures. Because they’re the perfect environment for bacteria to thrive and proliferate — dark and wet with plenty of food — effective disinfection, in general, is incredibly important to prevent spreading infection.

Drying’s role, specifically, is critical. When done effectively, meaning there’s no measurable moisture when the endoscope heads into surgery or storage, it limits the risk of bacteria from growing and helps keep the endoscope in its post-disinfected condition. When drying isn’t complete, it no longer matters how rigorously you follow other reprocessing steps. Any measurable moisture enables bacteria growth, particularly when the endoscope won’t be used immediately, increasing the risk of infection.[5]

Three Misconceptions About Endoscope Drying

1. Industry guidelines are the gold standard

Industry guidelines don’t include specific, constructive advice on how to produce a dry endoscope, leaving too much room for interpretation and error. For instance, AAMI states that flowing air through channels for a specified period will achieve drying, but the guideline doesn’t specify the period or what type of air would be most beneficial. [6]

2. Drying means dry

The words “drying” and “dry” are often synonymously used, but there is a distinct difference between the two. “Drying” is a process, whereas “dry” is a state of being. And while the two are interconnected, “drying” doesn’t guarantee “dry.”

Several industry studies investigate drying but don’t identify how to produce a dry endoscope. [2-5] The findings mostly reveal what isn’t effective and are often misconstrued to support inadequate drying practices.

3. All drying cabinets produce the same dry quality

Just as not every clothes dryer is of the same quality, not all drying cabinets are the same. Standard cabinets lack some of the critical functions automated cabinets offer, such as a constant flow of compressed, instrument-grade filtered air through internal channels and over external surfaces. It is otherwise known as an active dry system. With an active dry system, the environment is more controlled, forcing water to evaporate quickly and limiting the risk of bacteria growth. Without one, the environment within the cabinet is warm and humid, allowing bacteria to reproduce rapidly and biofilm to form.

The reprocessing process needs to incorporate an automated cabinet to get a dry endoscope efficiently. The risk of infection transmission is real. Reprocessing professionals and clinicians deserve to feel confident that every endoscope is safe for use on patients. And that means ensuring your drying process leads to a dry endoscope. Consult published articles to learn more about how you can elevate your drying practices to protect patients.

 This article was written by Darren Dahlin, Clinical Education Director at Medivators, the medical division of Cantel.



1 Thaker AM, Kim S, Sedarat A, et al. Inspection of endoscope instrument channels after reprocessing using a prototype borescope. Gastrointest Endosc 2018;88:612-619.

2 Barakat MT, Girotra M, Huang RJ, Banerjee S. Scoping the scope: endoscopic evaluation of endoscope working channels with a new high-resolution inspection endoscope (with video). Gastrointest Endosc 2018;88:601-611.

3 Ofstead CL, Wetzler HP, Heymann OL, Johnson EA, Eiland JE, Shaw MJ. Longitudinal assessment of reprocessing effectiveness for colonoscopes and gastroscopes: results of visual inspections, biochemical markers, and microbial cultures. Am J Infect Control 2017;45:e26-33.

4 In Hospital evaluation of contamination of duodenoscopes: a quantitative assessment of the effect on drying,” M.J. Alfa and D.L. Sitter, July 1991.

5 Kovaleva J, Endoscope drying and its pitfalls, Journal of Hospital Infection (2017), http://dx.doi.org/10.1016/j.jhin.2017.07.012

6 ANSI/AAMI ST91: 2015, Flexible and semi-rigid endoscope processing in health care facilities. Standard, Manual Drying, and Standard 6, Automated endoscope reprocessors.