Endoscope Reprocessing

In modern medicine, endoscopes have become indispensable tools for minimally invasive diagnostic and therapeutic procedures, enabling clinicians to access internal body structures with reduced patient trauma and faster recovery times. However, the reusable nature of these intricate devices poses a significant challenge: ensuring they are properly reprocessed to prevent healthcare-associated infections (HAIs). With over 250 million endoscopic procedures performed globally each year—and this number continuing to rise—the importance of rigorous endoscope reprocessing cannot be overstated. This comprehensive guide explores the fundamentals of endoscope reprocessing, the critical steps involved, current technologies, global standards, and modern solutions to enhance safety and efficiency.

What is Endoscope Reprocessing?

Endoscope reprocessing refers to the systematic cleaning, disinfection, or sterilization of reusable endoscopes between patient uses. Due to the complex design of endoscopes—particularly flexible and semi-rigid models, which feature narrow lumens, multiple channels, and delicate components—reprocessing requires precise handling and strict adherence to manufacturer-specific Instructions for Use (IFU). The primary goal of reprocessing is to eliminate or reduce pathogenic microorganisms (bioburden) to a safe level, thereby minimizing the risk of cross-contamination between patients.

Notably, the classification of endoscopes (critical, semi-critical, or non-critical) per the Spaulding Classification dictates the required level of reprocessing. While many flexible endoscopes are traditionally categorized as semi-critical (requiring high-level disinfection), certain procedures—such as those involving tissue biopsy, foreign body removal, or contact with sterile tissue—elevate them to critical devices, necessitating terminal sterilization. This distinction has become a key focus in global reprocessing standards, as documented outbreaks of multidrug-resistant microorganisms (MDROs) have frequently been linked to inadequate reprocessing of flexible endoscopes.

The 6 Essential Steps of Endoscope Reprocessing

Proper endoscope reprocessing is a sequential process where each step builds on the previous one to ensure maximum safety. Skipping or compromising any step can lead to residual contamination and increased infection risk. Below are the six core steps, as outlined in industry standards such as ANSI/AAMI ST91:2021.

1. Point-of-Use Treatment

Point-of-use treatment occurs immediately after the procedure in the examination room and is the first line of defense against tough-to-remove contaminants. Organic materials (e.g., blood, body fluids) left to dry on the endoscope become significantly harder to eliminate, reducing the effectiveness of subsequent disinfection or sterilization steps. This step involves:

· Wiping the endoscope’s external surface with non-linting cloths or wipes.

· Flushing and brushing accessible channels with a compatible pre-cleaning agent to reduce bioburden.

· Using ready-to-use kits (e.g., Revital-Ox™ Bedside Complete Pre-Cleaning Kit) for convenience and consistency.

Prompt point-of-use treatment is critical, as it sets the foundation for successful reprocessing by minimizing the buildup of biofilm and organic debris.

2. Leak Testing

Upon arrival in the reprocessing area, leak testing is performed to identify damage to the endoscope’s external surface or internal channels. A damaged endoscope cannot be properly reprocessed and may allow contaminants to enter, posing a risk to patients. Two common methods of leak testing are:

· Dry leak testing: Pressurizing the endoscope and using sensors to detect drops in pressure, indicating a leak.

· Wet leak testing: Submerging the pressurized endoscope in clean water and observing for bubbles, which signal a leak.

If a leak is detected, the endoscope must be removed from service and repaired in accordance with facility policies and manufacturer guidelines.

3. Manual Cleaning and Verification

Manual cleaning is widely regarded as the most critical step in reprocessing, as a dirty endoscope cannot be effectively disinfected or sterilized. When performed correctly, manual cleaning can reduce pathogen presence by up to 99.9%. Key components of this step include:

· Detaching all removable parts (e.g., valves, adapters) and immersing them in a compatible enzymatic detergent.

· Thoroughly brushing and flushing all channels and ports to remove debris—brushes must match the diameter of each channel to ensure full contact.

· Adhering to manufacturer-specified timeframes, temperatures, and detergent concentrations.

· Rinsing the endoscope and accessories with clean water to remove detergent residues.

· Verifying cleanliness through visual inspection (using magnification or borescopes for hard-to-see areas) and qualitative protein detection tests to identify residual organic material.

If debris or damage is found during verification, the endoscope must be re-cleaned or repaired before proceeding.

4. High-Level Disinfection (HLD) or Liquid Chemical Sterilization (LCS)

Following manual cleaning, the endoscope undergoes either HLD or LCS, depending on its classification and intended use. Per ANSI/AAMI ST91:2021, semi-critical devices require at minimum HLD if sterilization is not feasible, while critical devices demand sterilization.

· High-Level Disinfection (HLD): Eliminates all microorganisms except for high levels of bacterial spores. While HLD can be performed manually by soaking, automated endoscope reprocessors (AERs) are recommended for consistency. AERs (e.g., ADVANTAGE PLUS™ Pass-Thru Automated Endoscope Reprocessor) streamline the process by flushing cleaning and disinfectant agents through channels, with pass-thru designs minimizing cross-contamination between clean and dirty areas.

· Liquid Chemical Sterilization (LCS): Achieves a sterility assurance level (SAL) of 10⁻⁶ (meaning a 1 in 1,000,000 chance of a viable microorganism remaining) by immersing the endoscope in chemical agents such as glutaraldehyde, peracetic acid, or hydrogen peroxide. Systems like the SYSTEM 1™ endo Liquid Chemical Sterilant Processing System (LCSPS) automate this process for heat-sensitive semi-critical devices.

Both methods require strict adherence to agent concentration, temperature, and contact time to ensure effectiveness.

5. Drying and Storage

Proper drying is essential to prevent microbial growth and biofilm formation, as residual moisture can allow surviving microorganisms to multiply to dangerous levels (over 1 million colony-forming units in just a few hours). After HLD or LCS, the endoscope must be thoroughly dried, including purging channels with air to remove trapped water. Storage requirements, as specified by ANSI/AAMI ST91:2021, include:

· Suspending endoscopes vertically or horizontally in a dedicated storage cabinet to allow air circulation.

· Ensuring cabinets have channel purging capabilities to maintain dryness.

· Following manufacturer guidelines for storage duration and conditions.

High-quality water is critical during rinsing and drying, as suboptimal water quality can introduce contaminants and foster biofilm growth.

6. Transport

The final step in reprocessing is the safe transport of the reprocessed endoscope to the procedure room. Improper transport can lead to recontamination, requiring the entire reprocessing cycle to be repeated. Key transport practices include:

· Performing hand hygiene and wearing new gloves before handling the reprocessed endoscope.

· Loosely coiling the endoscope to avoid damaging channels or insertion tubes.

· Placing the endoscope in a clean, covered, solid transport container (large enough to accommodate the device without over-coiling) if transported through non-controlled areas.

· Clearly identifying the container as holding a clean, reprocessed endoscope.

Current Reprocessing Technologies: Liquid Chemical Sterilization vs. Terminal Sterilization

The debate over the most effective reprocessing method for flexible endoscopes has centered on two approaches: liquid chemical sterilization (LCS) and terminal sterilization. While LCS has been widely used, its limitations—including the lack of a sterile barrier (leaving devices vulnerable to environmental contamination before use) and challenges in verifying SAL—have led to a global trend toward terminal sterilization for critical applications.

Liquid Chemical Sterilization (LCS)

LCS involves immersing cleaned endoscopes in chemical sterilants under controlled conditions (concentration, temperature, time) to achieve SAL 10⁻⁶. Common agents include glutaraldehyde, ortho-phthaldehyde (OPA), and peracetic acid. While effective for some devices, LCS faces significant challenges with flexible endoscopes, such as ensuring adequate contact time in narrow lumens, potential bioburden interference with sterilant concentration, and water retention in channels (which promotes biofilm growth). Advanced AERs with HEPA filters and pass-thru systems have improved LCS workflows but do not address the core limitation of no sterile barrier.

Terminal Sterilization

Terminal sterilization delivers SAL 10⁻⁶ and maintains sterility until the point of use by enclosing the endoscope in a sterile barrier that allows sterilant diffusion. Conventional steam sterilization is not feasible for flexible endoscopes due to high temperatures, so low-temperature technologies are preferred. Key options include:

· Ethylene Oxide (EO): Effective for long or complex endoscopes but has drawbacks, including long aeration times (12–36 hours), environmental concerns, and strict occupational safety regulations.

· Vaporized Hydrogen Peroxide (VHP) and Hydrogen Peroxide Plasma (HPP): Offer fast cycle times (under 1 hour) but are limited by endoscope length (typically <100 cm) and channel count. Recent advancements (e.g., ASP’s Sterrad system compatibility with a specific Pentax duodenoscope) have expanded their use.

· Low-Temperature Steam Formaldehyde (LTSF): Combines the benefits of EO (compatibility with long endoscopes) and VHP/HPP (manageable cycle times ~90 minutes). Operating at 50–80°C, LTSF uses a steam-formaldehyde mixture to inactivate microorganisms and includes a two-stage residual removal process. It has no restrictions on endoscope length or channel count, making it a promising alternative for critical procedures.

Source: Authors.

Source: Modified from Lorenzo et al. NSW SRACA Conference 18th-20th March Opal Cove, Coffs Harbour. HPP*: In September 2024, compatibility of one specific Pentax Duodenoscope (only sold in the US) with ASP Sterrad VHP system was announced.

Global Standards and Guidelines for Endoscope Reprocessing

To address the risks associated with inadequate reprocessing, global organizations and regulatory bodies have established standards and guidelines to ensure consistency and safety. These standards emphasize staff training, rigorous protocol adherence, and the transition to terminal sterilization for critical procedures.

United States

The U.S. Food and Drug Administration (FDA) acknowledges that liquid chemical sterilization does not provide the same SAL assurance as low-temperature thermal or gas/vapor/plasma sterilization. The Association for the Advancement of Medical Instrumentation (AAMI) published ANSI/AAMI ST91 in 2015, a comprehensive framework for flexible endoscope reprocessing that covers HLD, LCS, and terminal sterilization. Updated in 2021, this standard is partially recognized by the FDA and emphasizes staff competency, cleaning verification, and microbiological surveillance.

Australia

Australian Standard AS5369 mandates that critical reprocessable medical devices incompatible with moist heat sterilization must undergo validated low-temperature sterilization between uses. Approved methods include peracetic acid, hydrogen peroxide, and LTSF.

Europe

The European Society of Gastroenterology and Endoscopy Nurses and Associates (ESGENA) explicitly recommends against liquid chemical sterilization for endoscopes due to the lack of a sterile barrier. ESGENA also stresses the importance of water quality during final rinsing to maintain SAL. Manufacturers such as Olympus and Pentax have integrated these recommendations into their IFUs, solidifying the shift toward terminal sterilization in Europe.

Modern Solutions: Digital Tracking and Automation

While adhering to the six core reprocessing steps is fundamental, modern healthcare facilities face additional challenges in managing endoscope inventory, ensuring compliance, and reducing manual errors. Digital tracking systems like ScopeCycle® have emerged as critical tools to address these challenges by integrating with reprocessing workflows to enhance accountability and efficiency.

Key features of digital tracking systems include:

· Real-time tracking: Monitors endoscopes from storage through reprocessing and transport, providing full visibility into the device’s lifecycle.

· Automated documentation: Eliminates manual record-keeping errors by logging disinfection cycles, storage times, and staff interactions.

· Compliance support: Aligns with guidelines from SGNA, CDC, and Multi-Society, providing comprehensive reporting for quality assurance audits.

· Staff competency monitoring: Tracks training and certification to ensure only qualified personnel perform reprocessing tasks.

· Inventory management: Optimizes endoscope utilization by providing insights into device availability, maintenance needs, and repair history.

Cloud-based accessibility and integration with existing hospital systems make these solutions cost-effective and easy to implement, enabling facilities to streamline operations while enhancing patient safety.

The Future of Endoscope Reprocessing

As endoscopic procedures continue to grow in volume and complexity—driven by the rising prevalence of chronic diseases, obesity, and expanded early detection programs—the demand for safe, efficient reprocessing will only increase. The future of endoscope reprocessing lies in the integration of three key elements:

1. Rigorous adherence to evidence-based best practices for manual cleaning and reprocessing.

2. Wider adoption of terminal sterilization technologies (e.g., LTSF) for critical procedures to minimize infection risk.

3. Implementation of advanced digital tracking systems to enhance compliance, accountability, and operational efficiency.

While transitioning to terminal sterilization may require additional investment in endoscopes and equipment, the long-term benefits—reduced HAIs, improved patient outcomes, and potential cost savings from fewer adverse events—outweigh the costs. In pay-for-performance healthcare systems, this transition may also lead to higher reimbursement rates by demonstrating a commitment to patient safety.

Conclusion

Endoscope reprocessing is a critical component of patient safety, requiring meticulous attention to detail, adherence to global standards, and the use of effective technologies. By following the six essential steps—point-of-use treatment, leak testing, manual cleaning and verification, HLD/LCS, drying and storage, and transport—healthcare facilities can minimize the risk of cross-contamination. The global shift toward terminal sterilization and the integration of digital tracking systems further enhance safety and efficiency, ensuring that endoscopes remain valuable tools for minimally invasive care without compromising patient well-being.

Remember, every step in the reprocessing journey matters. By prioritizing best practices and leveraging modern solutions, healthcare providers can uphold the highest standards of patient safety and deliver exceptional care.