ChannelCheck Verification Test as a Tool to Assess Endoscope Cleanliness


The purpose of this study was to determine the real-world effectiveness of healthcare facilities flexible endoscope cleaning procedures by utilizing the ChannelCheck residual soil test, a product of Healthmark Industries Co, Inc. The ChannelCheck test detects the presence of organic contaminants and can serve as a quality control tool to identify potential deficiencies in endoscope reprocessing effectiveness, typically failure results from not following reprocessing standards and guidelines or the use of damaged or defective equipment.

By Natalie N. Whitfield, PhD

Objective: The purpose of this study was to determine the real-world effectiveness of healthcare facilities flexible endoscope cleaning procedures by utilizing the ChannelCheck residual soil test, a product of Healthmark Industries Co, Inc. The ChannelCheck test detects the presence of organic contaminants and can serve as a quality control tool to identify potential deficiencies in endoscope reprocessing effectiveness, typically failure results from not following reprocessing standards and guidelines or the use of damaged or defective equipment.

Study Design: A total of 12 healthcare facilities were recruited to participate in this study. At each facility, the instrument/suction channel of 10 endoscopes was tested using the ChannelCheck product before and after cleaning, but prior to high-level disinfection. The ChannelCheck product tests the presence of three organic contaminants, including carbohydrate, hemoglobin and protein. Following ChannelCheck testing at each facility, participants completed a survey identifying the reprocessing methods used at the facility.

Results: Of the 120 endoscopes tested, cleaning removed the majority of the residues detected prior to manual cleaning of the endoscopes. The most common residue found before manual cleaning was hemoglobin, (54 percent or 65 endoscopes); however after the cleaning procedure only 4 percent (five endoscopes) of these endoscopes yielded a positive result for hemoglobin. The endoscopes that were positive for organic residue post-cleaning were positive for one or two residues; however, one gastroscope was positive for all three soils, both before and after the cleaning process.

Conclusion: The ChannelCheck is an easy to use and effective tool for monitoring the endoscope cleaning process and demonstrating competency of facility reprocessing staff.

Background. In the United States, there are an estimated 34 million gastrointestinal (GI) endoscopy procedures performed annually (Lieberman, De Garmo, Fleischer, Eisen, & Helfand, 2000) (Owings and Kozak, 1998) (Seeff, et al., 2004). Although the estimated risk of transmission of infection during endoscopy is extremely low (Nelson and Muscarella, 2006), flexible endoscopes are still an important concern. Most infections have been linked to errors occurring during reprocessing events, in particular cleaning procedures (Nelson, et al., 2003). More recently, several headlines have highlighted the importance of decreasing the potential risk of cross-contamination from endoscopy procedures.

Because patient safety is of critical concern when reprocessing endoscopes, several guidelines and standards have been established to ensure that proper reprocessing is performed (SGNA, ASGE, APIC, AORN and ASTM) (SGNA, 2009) (Nelson, et al., 2003). However, without proper training and failure to adhere to the established guidelines there is an increased risk of survival of microorganisms and infection (Alfa, 2006). In addition, failure to properly clean an endoscope can potentially inhibit the subsequent disinfection and sterilization processes:

"Thorough cleaning are the first and most important steps in the reprocessing of any reusable medical device. Without thorough cleaning it is not possible to achieve high-level disinfection or sterilization of the device. The purpose of cleaning and rinsing is to remove all adherent visible soil..." (AAMI TIR12, 2004)

"Of particular significance is the need to thoroughly manually clean equipment prior to any manual or automated disinfection or sterilization process." (Endoscopy Working Group, 2000)

"two colonoscopy patients were infected with hepatitis CThe investigation concluded that the biopsy channel had not been properly cleaned and the disinfection failed." (Bronowicki, et al., 1997)

The adherent soils that may result from microorganisms, patient material or both, if not removed may potentially induce pyrogenic and anti-genic reactions in a patient. Residual organic material following cleaning may also become attached to the device surfaces as a result of the sterilization or disinfection process. The most widely used chemistries for high-level disinfection are aldehyde-based chemistries, which fix organic material on the surface. This fixed material may offer protection for underlying microorganisms from exposure to the disinfectant or sterilant (ANSI/AAMI ST79, 2009).

Endoscope design presents an inherent cleaning challenge due to the long, narrow lumens that are an integral part of their structure and function. Consequently, methods that allow reprocessing personnel to monitor their cleaning procedures are a necessary addition to their practice, which reduces risks associated with inadequate reprocessing of these devices. Several documented sources support the need for such methods to monitor the cleaning process:

"Because disinfection and sterilization cannot be assured unless the cleaning process is successful, professionals in the field ought to seek out whatever means are available and practical to verify this function" (ANSI/AAMI ST79, 2009)

"Cleaning verification by users should include (a) visual inspection combined with other verification methods that allow the assessment of both external surfaces and inner housing and channels of medical devices." (ANSI/AAMI ST79, 2009)

Currently, few products exist for this purpose. A successful verification test for acceptable endoscope cleaning must take into consideration the design of the endoscopes, be feasible for routine use, and be cost effective and easy to interpret. The objective of this study was to determine the usefulness of the ChannelCheck test strip to monitor the success of endoscope cleaning procedures.

Round-Robin Study Method. Healthcare centers (hospitals, ambulatory care centers, and endoscopy clinics) across the U.S. that showed interest in participating, were recruited to assess the use of the ChannelCheck as a method to determine whether proper cleaning of patient-used endoscopes was accomplished. Participants likely have an increased interest in proper reprocessing, demonstrated by their willingness and choice to participate in this study. Participants from the healthcare centers tested the instrument channel of 10 endoscopes twice; first, after bedside cleaning following the patient procedure, and second, immediately after manual cleaning, but prior to high-level disinfection or sterilization. The endoscopes were tested by flushing the instrument/suction channel with sterile deionized water and immersing the test strip in the flush fluid for 10 seconds. The ChannelCheck test strips, used for verification testing, detect the presence of protein, carbohydrates, and hemoglobin in approximately 90 seconds. A color change on any of the three pads indicates a positive result requiring that the endoscope be re-cleaned due to the presence of organic residues from patient or microorganism contamination. Participants were also supplied with a log sheet to record all results. Upon completion of their testing, participants were asked to return log sheets and respond to a survey regarding details of their reprocessing procedures.

Results. The most common type of endoscope used by the study participants was a colonoscope, which accounted for 68 (57percent) of the total endoscopes tested (See Table 1). Of the 120 endoscopes tested, the most prevalent organic residue found on endoscopes, following bedside precleaning, was hemoglobin (64 percent). Colonoscopes and gastroscopes presented the greatest challenge at removing organic material from lumens (See Figure 1A). However, residual hemoglobin was routinely removed following manual cleaning procedures (See Table 2). Protein and carbohydrates were found in about 30 percent of the endoscopes before manual cleaning. Likewise, manual cleaning effectively removed the residual protein and carbohydrate contaminants present (See Figure 1B). Only five endoscopes showed residues remaining after manual cleaning, primarily gastroscopes. One gastroscope was positive for all three residues after bedside cleaning and also after manual cleaning (See Figure 1). Endoscopes with a positive ChannelCheck test were re-cleaned, in which case they passed and were terminally high-level disinfected or sterilized.

Survey Summary. Participants that responded to the survey were highly satisfied with the ChannelCheck and found the product easy to use. Most participants indicated they would incorporate the ChannelCheck into their process either daily, weekly or for staff proficiency and competency evaluations. Participants also provided more detailed information on their reprocessing methods by responding to additional questions (See Appendix 1). All survey respondents indicated that they follow SGNA guidelines (SGNA, 2009). However, none of the participants currently utilize a test to independently confirm that their scopes are thoroughly cleaned, suggesting the necessity for such a method. In summary, the ChannelCheck is an easy to use and interpret addition to the cleaning process that allows users to demonstrate competency with proper reprocessing methods of endoscopes.

Discussion. Implementing a method to assess proper cleaning of flexible endoscopes is essential to insuring effective reprocessing and reducing the risk of patient infection. As a part of endoscope reprocessing, verification allows the staff to monitor critical steps. This study demonstrates the feasibility of a verification test to indicate whether there has been a breach in the cleaning protocol of endoscopes and whether endoscopes are sufficiently clean, prior to terminal high-level disinfection or sterilization.

Five endoscopes tested positive for organic contaminants after cleaning but prior to terminal reprocessing, indicating that there may have been breach in the manual cleaning process. However, once tested using the ChannelCheck, the contaminated endoscopes were re-cleaned and tested negative, indicating that a rigorous cleaning process is capable of rendering an endoscope suitable for the succeeding steps. In addition, this verification test was a key identifier of a breach in the cleaning procedure or indicative of an endoscope that was difficult to clean or required more extensive manual cleaning.

Survey results illustrate little similarity or consistency in the reprocessing methods of the participants, both in manual cleaning and automated final processing. Various differences in process from facility to facility included detergent contact-time, channel brushing and flushing repetitions, final rinse reagent, and use of disposable or reusable brushes. The use of an objective, standardized method for the cleaning process, by all, is beneficial, yet impractical due to the obvious variations in the reprocessing of endoscopes by individuals, equipment, and healthcare centers. Therefore, the ChannelCheck is a valuable tool to scrutinize proper cleaning techniques for training purposes, competencies, or simply, routine surveillance of the process.

Natalie N. Whitfield, PhD, is with Healthmark Industries Co, Inc.

Table 1. Most Common Types of Endoscopes Tested in Study

Type of Endoscope/Number Tested After Procedure by Participating Facilities

GI Endoscopes/103








Table 2. Endoscopes Positive for Organic Residues

Organic Residue

Endoscopes Positive after Bedside Cleaning

Carbohydrate: 30 (25%)

Protein: 38 (32%)

Blood: 65 (54%)

Endoscopes Positive after Manual Cleaning

Carbohydrate: 1 (<1%)

Protein: 3 (2.5%)

Blood: 4 (3%)

Total scopes tested: 120


AAMI TIR12. (2004). Designing, testing, and labeling, reusable medical devices for reprocessing in healthcare facilities. AAMI TIR12:2004 . Arlington, VA: Association for the Advancement of Medical Instrumentation.

ANSI/AAMI ST37-1996. (1996). Flash sterilization: steam sterilization of patient care items for immediate use. ANSI/AAMI ST37-1996 . Arlington, VA: Association for the Advancement of Medical Instrumentation.

ANSI/AAMI ST79. (2009). Comprehensive guide to steam sterilization and sterility assurance in healthcare facilities. ANSI/AAMI ST79:2009 . Arlington, VA: Association for the Advancement of Medical Instrumentation.

Bronowicki, J., Venard, V., Botté, C., Monhoven, N., Gastin, I., Choné, L., et al. (1997). Brief Report:Patient-to-Patient Transmission of Hepatitis C Virus during Colonoscopy. The New England Journal of Medicine, 237-240.

Clark, C. (2010, June 16). Hospital Sends Letters to 3,400 Patients About Possible Endoscopic Equipment Contamination. Retrieved June 25, 2010, from Health Leaders Media:

Cullen, K., Hall, M., & Golosinskiy, A. (2009). Ambulatory Surgery in the United States, 2006. National health statistics reports; no 11. Revised. Hyattsville, MD: National Center for Health Statistics.

Department of Veterans Affairs. (2009). Use and Reprocessing of Flexible Fiberoptic Endoscopes at VA Medical Facilities. Washington DC: Office of the Inspector General.

Endoscopy Working Group. (2000). Guidelines for Infection Prevention and Control in Endoscopy. Manitoba Advisory Committee on Infectious Diseases. Manitoba Health Public Health.

Favero, M., & Bond, W. (1991). Sterilization, disinfection, and antisepsis in the hospital. In H. W. Balows A, Manual of Clinical Microbiology 5th edition (pp. 183-200). Washington DC.

Lieberman, D., De Garmo, P., Fleischer, D., Eisen, G., & Helfand, M. (2000). Patterns of endoscopy use in the United States. Gastroenterology (118), 619-624.

Nelson, D., & Muscarella, L. (2006). Current issues in endoscope reprocessing and infection control during gastrointestinal endoscopy. World Journal of Gastroenterology , 12 (25), 3953-3964.

Nelson, D., Jarvis, W., Rutala, W., Foxx-Orenstein, A., Isenberg, G., Dash, G., et al. (2003). Multi-society Guideline for Reprocessing Flexible Gastrointestinal Endoscopes. Infection Control and Hospital Epidemiology, 532-537.

Owings, M., & Kozak, L. (1998). Ambulatory and inpatient procedures in the United States, 1996. Vital Health Statistics, 13, 1-119.

Rutala WA, Webber DJ, Healthcare Infection Control Committee. (2008). Guideline for Disinfection and Sterilization in Healthcare Facilities.

Seeff, L., Manninen, D., Dong, F., Chattopadhyay, S., Nadel, M., Tangka, F., et al. (2004). Is there endoscopic capacity to provide colorectal cancer screening to the unscreened population in the United States? Gastroenterology (127), 1661-1669.

SGNA. (2009). Standards of Infection Control in Reprocessing of Flexible Gastrointestinal Endoscopes. Chicago: Society of Gastroenterology Nurses and Associates.

Standards, Recommended Practices, Guidelines. (1999). Denver: Association of Operating Room Nurses.

23. Do you follow SGNA procedures for endoscope reprocessing?

22. Which channels do you test?

21. How frequently do you test your endoscopes?

20. Do you currently utilize a test to independently confirm that endoscopes are thoroughly cleaned?

19. What is used for the final rinse?

18. What was the temperature for contact with the disinfectant?

17. How long are the endoscopes soaked in disinfectant?

16. What type of disinfectant is used?

15. What type of final process does your facility use?

14. What is used for the final rinse in the manual cleaning process?

13. Are disposable brushes used?

12. How many times are the channels flushed?

11. How many times are the channels brushed?

10. What is the contact time for the cleaning agent used?

9. What type of detergent is used?

8. What type of container are they transferred in?

7. Are the endoscopes transferred after use to a separate cleaning room?

6. What type of cleaning agent is used?

5. How are the endoscopes manually cleaned at bedside?

4. Who is primarily responsible for reprocessing endoscopes at your facility?

3. Which channels would you test?

2. How easy was it to interpret the results of this product?

1. How easy was this product to use?

Appendix 1. Reprocessing Methods Survey--Sample Questions



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