Common errors in endoscope reprocessing usually appear at seven in the evening, when there is an emergency colonoscopy and only one piece of equipment is available. The nurse receives it still wet with organic matter, quickly runs it through the washer, and puts it away. No one did anything "serious," but that piece of equipment is now at risk. **Common errors in endoscope reprocessing** are almost never spectacular oversights: they are small shortcuts, repeated shift after shift. The good news is that each one has an identifiable cause and a concrete correction, and that is what you will find here.

Why reprocessing fails in practice

Reprocessing fails because it combines many manual steps, strict contact times, and equipment with internal channels that cannot be seen. It only takes one step being shortened due to clinical pressure for the entire cycle to lose its effectiveness, even if the rest is done correctly.

A flexible endoscope is not a smooth surgical instrument. It has air, water, suction, and biopsy channels less than a few millimeters in diameter, removable valves, an elevator in duodenoscopes, and junctions where fluid can pool. Anything that is not brushed, irrigated, or dried can retain biofilm, and biofilm protects microorganisms from the disinfectant.

This is why failures usually have recurring roots: too few trained staff, high turnover, overly tight times between procedures, supplies that do not match the equipment model, and a lack of records. It is rarely due to bad intentions. It is almost always a process designed without any margin for error.

The consequences for the patient range from mild discomfort to cross-infection. Complications associated with endoscopy include perforation, bleeding, and infections, and it is precisely these last ones that proper reprocessing prevents. If you are looking for the complete step-by-step process, that is the role of a process guide; here, the focus is on what is done wrong and how to prevent it. For general context on the instrument, you can consult the Wikipedia entry on the endoscope.

Insufficient cleaning before disinfection

The most frequent and serious error is disinfecting without having cleaned properly. No high-level disinfectant works through dried blood, mucus, or bile residue: manual cleaning removes the organic load and is the foundation for everything that follows.

This is what is most frequently seen in endoscopy departments:

• Late pretreatment. 30 or 60 minutes pass between the end of the procedure and cleaning. Fluids dry and adhere to the channel. Initial cleaning in the room, with detergent aspiration and external cleaning, should be immediate.
• Improperly diluted detergent. It is measured "by eye." Too much creates foam that makes rinsing difficult; too little means the detergent does not dissolve the organic matter.
• Incomplete brushing. It is brushed only once, or with a brush of the wrong diameter, or a disposable brush is reused. The brush should come out clean from the other end of the channel.
• Leak test omitted. If the equipment has a micro-perforation in the sheath, liquid enters and damages internal components. It is a short step that many skip.

A practical criterion: if you still see residue on the brush or in the rinse liquid, the channel is not clean, no matter how long you have brushed. Some departments complement this with rapid tests for organic residue on the channel; it is a useful verification, not a substitute for brushing.

Endoscope cleaning failures also skyrocket when staff do not know the model. Each manufacturer defines which channels it has, which brushes to use, and how to disassemble the valves. Anyone working with Olympus endoscopy equipment should always have the reprocessing instructions for the exact model at hand, not a generic version for another piece of equipment.

Before touching the detergent, it is worth checking the clock. In many departments, late pretreatment does not stem from negligence but from the schedule: the next patient is already waiting in the room, and the technician has to choose between cleaning properly or keeping to the schedule. If the shift does not leave time for reprocessing, common errors in endoscope reprocessing become routine. A simple adjustment is to reserve a fixed time between studies for initial cleaning, and to have that time appear in the schedule like any other activity.

Use of disinfectant at the wrong concentration or for the wrong amount of time

The second major group of failures is with the disinfectant: concentration below the minimum effective level, shortened contact time, or expired product. In any of the three cases, the equipment comes out wet and appears clean, but without a guarantee of high-level disinfection.

The most common errors when disinfecting endoscopes are these:

Error	What happens	How to avoid it
Not measuring the minimum effective concentration	The disinfectant is diluted with use and ceases to be effective	Use test strips according to the manufacturer's instructions and record each result
Reusing the solution beyond its useful life	It loses activity even if it does not look different	Label the opening and expiration dates on the container
Shortening the immersion time	The contact time is not enough to eliminate resistant microorganisms	Time it with a visible timer, not from memory
Channels not filled with disinfectant	Air bubbles prevent internal contact	Irrigate all channels until you see the liquid come out
Final rinse with unsuitable water	Recontamination of the already disinfected equipment	Use water of the quality defined by the department and filters when applicable

In automatic washers, the classic error is blindly trusting the machine. The washer does not clean what was not cleaned by hand, and it needs its own controls: correct connectors for each channel, changed filters, validated cycles, and verified disinfectant. If a connector is improperly placed, an entire channel may not receive liquid, and the cycle will end as "successful" on the screen.

For the Pan American Health Organization and local health authorities, the prevention of healthcare-associated infections depends on standardized and traceable processes. A record per piece of equipment, with the date, operator, cycle, and control results, is what allows you to reconstruct what happened if a suspicious case appears.

Incorrect drying and storage

An endoscope stored wet is a potential culture. Incomplete drying of the channels allows microorganisms that survived to multiply during storage, and this turns a good disinfection cycle into a subsequent problem.

Typical errors at this stage are less visible than the previous ones, which is why they go on for longer without being corrected:

• Drying only the outside with a wipe and leaving the channels damp.
• Omitting the alcohol rinse and purging with filtered air at controlled pressure.
• Storing the equipment coiled, inside its transport case, or with the valves attached.
• Using cabinets without ventilation or periodic cleaning, or hanging them so they touch the walls.
• Not recording the time since the last reprocessing, so no one knows if the equipment has "expired" for use.

The transport case deserves a separate mention: it is designed to transport the equipment, not to store it. In a closed case, residual moisture gets trapped, and the foam interior can become a reservoir of contamination. Correct storage is vertical, hanging, in a clean, dry, and ventilated cabinet, with the valves removed or placed as indicated by the manufacturer.

If the department has not defined how long a piece of equipment can remain hanging before being reprocessed, that is a frequent gap. The timeframe depends on institutional policy and the recommendations of the manufacturer and current guidelines. 

How to prioritize common errors in endoscope reprocessing

Not all errors carry the same weight, and treating them as if they were equal is another way to waste time. A channel with organic residue or a failed leak test are reasons to remove the equipment from circulation before using it again. A dirty cabinet or an incomplete record should also be corrected, although with less urgency. If your team has too few staff to audit everything, start with the points that directly affect the channel, because that is where the risk of cross-infection is concentrated.

Common errors in endoscope reprocessing: channels and valves

Channels and valves concentrate most technical failures: they are poorly brushed, incompletely disassembled, or replaced with parts that do not match the model. They are the areas with the most biofilm and the ones that are least visible.

A common scene: a suction valve with a dark residue at the base that no one checked because "the equipment has already come out of the washer." Or a biopsy channel damaged by an improper metal brush, with internal scratches where dirt later accumulates. What follows are the most repeated errors:

1. Reusable valves not disassembled. Pistons, springs, and gaskets are washed assembled, and dirt remains between the parts.
2. Disposable valves reused. If the manufacturer defines them as single-use, reusing them breaks the process from the start.
3. Brushes of the wrong size or material. Very small ones do not drag out residue; very hard ones scratch the channel.
4. Duodenoscope elevator not actuated. The elevator channel requires specific maneuvers, and without them, a critical area remains uncleaned.
5. Undetected damage. A channel with scratches, an insertion tube with folds, or a deteriorated gasket should have the equipment removed from circulation and sent for technical review.

This applies to the entire family of equipment. Gastrointestinal endoscopes are those used to examine the digestive tract: gastroscopes for the esophagus, stomach, and duodenum, colonoscopes for the large intestine, and duodenoscopes for the biliary tract. Each type has different channels and critical points, so the protocol cannot be identical for all. When the department operates with an Olympus endoscopy tower, or with a more recent one like the Olympus endoscopy tower 190, it is advisable that the reprocessing flow be aligned with the endoscope models that are actually used in each room.

A detail that surprises many: the equipment is also contaminated in the room, before and after the patient. When introducing the endoscope, which is done with the patient sedated and in the indicated position, guiding the insertion tube with water-soluble lubricant orally or rectally depending on the study, the instrument touches gloves, the stretcher, and surfaces. If subsequent handling mixes dirty and clean areas, what had already been reprocessed is recontaminated.

Audits to detect common errors in endoscope reprocessing

The most effective way to reduce errors is to audit the process regularly and correct it immediately, without waiting for something to go wrong. A useful audit combines direct observation, record review, and physical verification of the equipment and the environment.

A simple scheme you can set up without major investments:

• Direct observation. A person with a checklist watches a complete reprocessing, from beginning to end, without intervening. They note which steps are omitted or shortened.
• Record review. Each piece of equipment must have traceability: patient, date, cycle, operator, disinfectant concentration. Gaps in the records usually reveal gaps in the process.
• Physical verifications. Organic residue tests, borescope inspection of the channels when available, and visual review of valves and connectors. 
• Surveillance cultures. According to institutional policy and applicable guidelines, some departments take periodic samples from the equipment. The frequency is defined by the infection committee.
• Training and competencies. Evaluate each person who reprocesses, with a practical demonstration, and repeat it when an equipment model or supply changes.

When you find a failure, do not stop at pointing out the person. First ask what in the process made the error possible: were brushes missing?, was the timer too far away?, did the shift not leave time between studies? Correcting the system works better than reprimanding the operator, and prevents the same error from reappearing with another person.

Finally, document what is done if a piece of equipment fails a control: it is removed from circulation, reprocessed, investigated, and the infection committee and the manufacturer or technical provider are notified when appropriate. 

To start this week, print a checklist with the cleaning, disinfection, and drying steps of the model you use most, and observe a complete reprocessing without announcing the reason. What you see in that first observation will tell you what common errors in endoscope reprocessing your department has and where to start correcting.

Frequently asked questions

What complications can endoscopy cause?

Endoscopy is a safe procedure, but it can cause mild discomfort such as distension or sore throat, and less frequently bleeding, perforation, or reactions to sedation. There is also a risk of infection when the endoscope is not reprocessed correctly, which is why cleaning and disinfection are part of patient safety.

How do you disinfect an endoscope?

First, an immediate pretreatment is done in the room, then a leak test and manual cleaning with detergent, brushing and irrigating all channels. This is followed by high-level disinfection with the indicated product and time, rinsing, drying with alcohol and air, and hanging storage. The manufacturer's instructions for the model are always followed.

How is the endoscope introduced?

With the patient sedated or under local anesthesia, the lubricated insertion tube is introduced through the mouth in a gastroscopy or through the rectum in a colonoscopy. The specialist guides it by looking at the image on the monitor, using air or water to clear the view. The technique and preparation depend on the type of study.

What are gastrointestinal endoscopes?

They are flexible endoscopes designed to examine the digestive tract. They include gastroscopes for the esophagus, stomach, and duodenum, colonoscopes for the colon, and duodenoscopes for the biliary and pancreatic tract. They have air, water, suction, and accessory channels, which require careful reprocessing after each use.

What is the most frequent error in endoscope reprocessing?

Insufficient manual cleaning before disinfection. If organic matter remains in the channels or valves, the disinfectant cannot act and the process loses its effectiveness. It is usually due to late pretreatment, incomplete brushing, or improperly diluted detergent, and it is corrected with training, protected times, and checklists.

How often should endoscope reprocessing be audited?

There is no single frequency: it depends on the institution's policy, the volume of procedures, and the applicable guidelines. It is recommended to audit periodically and according to a schedule, and immediately when equipment, supplies, or personnel change, or when a suspected infection event occurs.