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Cleaning Verification: If It’s Not Clean It Can’t Be Sterilized

You have heard it over and over again: If it’s not clean, it can’t be sterilized or high-level disinfected (HLD). Previously, cleaning verification was hard to accomplish and therefore rarely completed by sterile processing (SP) personnel. Fortunately, easy-to-use cleaning verification tests that can be performed by frontline workers are readily available. Healthcare organizations have routinely used sterilization monitors (e.g., physical, chemical, and biological) to verify that sterilization or HLD conditions have been met; however, these monitors do not indicate if the items were properly cleaned, which we know is even more important. Therefore, verifying the cleaning processes should be routinely completed as part of the sterilization or HLD process.

The primary responsibility for developing and validating methods for effective reprocessing of reusable medical devices (e.g., instruments and endoscopes) is placed on the manufacturer of the device by the U.S. Food and Drug Administration. The device manufacturer is expected to validate that their instrument or equipment can be cleaned and disinfected or sterilized adequately for the device to be reused from one patient to another. Healthcare professionals who reprocess medical devices are considered users of the device. The users are expected to verify they are able to clean and sterilize or high-level disinfect instruments and equipment by meticulously following the manufacturer’s validated instructions for use (IFU). Available methods for user verification are described in Annex D of The Association for the Advancement of Medical Instrumentation’s (AAMI) Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities: ST79:2017.               

Validation vs. user verification
AAMI explains the difference between validation and user verification.

  • Validation: “Documented procedure performed by the device manufacturer for obtaining, recording, and interpreting the results required to establish that a process will consistently yield product complying with predetermined specifications.” (Section 2.131)
  • User verification: “Documented procedures, performed in the user environment, for obtaining, recording, and interpreting the results required to establish that predetermined specifications have been met.” (Section 2.129)1

Fortunately, there are many different methods of user cleaning verifications commercially available. ST79:2017 Annex D states:

“Verification of a cleaning process consists of

  1. defining a cleaning process and its critical aspects so that each step is fully verifiable through personnel training and observation to ensure that it can be followed completely, accurately, and without variation by all individuals who perform it;
  2. and providing process controls along with verification methodologies that ensure adequate, consistent cleaning levels.”1

Cleaning verification
Cleaning efficacy tests should be used to verify the ability of a cleaning process to remove or reduce to an acceptable level the organic soil and microbial contamination that occurs during the use of reusable devices. The effectiveness of both manual and mechanical cleaning processes should be monitored and documented on an ongoing periodic basis. Section in ST79:2017 states, “Mechanical cleaning equipment performance should be tested each day it is used and all results should be recorded.”

In my experience as a consultant, most SP departments and areas are performing daily cleaning verification tests for the efficacy of their automatic instrument washers, but only a few are testing daily the other types of automatic cleaning equipment, such as ultrasonics or cart washers. Automatic cleaning equipment tests indicate that the machine is working properly but they do not verify that the instruments have actually gotten clean. Users should also perform routine quality checks of the instruments and other devices for cleanliness. It is the same standard behind using internal chemical indicators (CIs) for sterilized packages. Internal CIs ensure the sterilant actually reached the inside of the packs, where external CIs only show the package was exposed to the sterilant. Rarely do I see cleaning verification testing being completed on items that have been manually cleaned and, in my opinion, these are often fraught with human errors due to time constraints, hard-to-follow IFUs, and lack of competencies.

Cleaning efficacy tools
There are several commercially available methods that can be used to evaluate the results of the cleaning process (e.g., protein, adenosine triphosphate [ATP], carbohydrate) on devices that have been mechanically cleaned or manually cleaned. AAMI provides a list of available in-use tests to assess efficacy of cleaning of medical devicesin ST79 in Annex D titled “User verification of cleaning processes.”1

The most common method is a visual inspection, often involving the use of a lighted magnifying glass which might identify residues more readily than the unaided eye. However, visual inspection alone may not be sufficient for assessing the efficacy of cleaning processes. Residual organic soil might be present even though the device looks clean. Moreover, visual inspection is not possible for the inner components of devices that have lumens (e.g., laparoscopic instruments, flexible endoscope channels).

Ideally, cleaning verification by users should include:

  • visual inspection and other verification methods that allow the assessment of both external surfaces and inner housing, and channels of medical devices;
  • and monitoring key cleaning parameters (e.g., temperature).

Internal channels of lumened devices and flexible endoscopes should be inspected using an endoscopic camera or borescope. Borescopes penetrate the lumen and allow for improved visual inspection. Fortunately, rigid and flexible borescopes with multiple articulation and diameter options are now commercially available. Borescopes are an important tool to help verify the internal lumens of instruments and endoscopes are clean and ready for the next processing step.

Without the help of cleaning verification tools we cannot assure a device is safe to use on patients. As part of a quality improvement process, the effectiveness of both manual and mechanical cleaning processes should be monitored and documented on an ongoing, periodic basis. Healthcare organizations that perform sterilization and or HLD should implement a quality system that routinely includes manual and mechanical cleaning verification tests to reduce patient risks to infection transmissions. The results of the tests should be documented.  


  1. Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities, ANSI/AAMI ST79:2017





Rose Seavey, MBA, BS, RN, CNOR, CRCST, CSPDT, is president/CEO of Seavey Healthcare Consulting and formerly the director of the SPD at The Children’s Hospital of Denver. Rose served on the AORN board of directors and is a past president ASHCSP. She received numerous awards and was named as one of the Who’s Who in Infection Prevention by Infection Control Today. Ms. Seavey is the author of Sterile Processing In Healthcare Facilities: Preparing for Accreditation Surveys, published by AAMI. She serves on several AAMI committees helping to write national standards.


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