Verification of Instrument Cleaning Processes

The old saying “If it is not clean it can’t be sterilized”, is extremely true.  Sterile Processing departments (SPD) routinely use physical, chemical and biological monitors to verify sterilization conditions are met. Nevertheless, these monitors do not monitor if the items were properly clean prior to being placed in a sterilizer.

The U.S. Food and Drug Administration (FDA) places the primary responsibility for developing and validating methods for effective reprocessing of reusable medical devices (e.g., instruments and endoscopes) on the manufacturer of the device. Instrument manufacturer must validate their instruments for cleaning and sterilization prior to obtaining a 510K clearance from the Food and Drug Administration (FDA).

Sterile Processing professionals are expected to “verify” they are able to clean and sterilizer instruments using the automatic cleaning equipment and manual cleaning processes according to the manufacturer’s instructions for use (IFU).

SPD should use commercially available efficacy tests to verify the ability of a cleaning process to remove organic soil and reduce microbial contamination. The cleaning effectiveness of both manual and mechanical processes should be monitored and documented on an ongoing periodic basis (e.g. daily or weekly).

Most SPDs routinely perform cleaning tests for the automatic washers. However, facilites are not always routinely testing the other types of cleaning equipment such as ultrasonics or cart washers which are just as important.

Keep in mind the automatic equipment tests only indicate that the machine is or is not working properly. They do not actually tell if the instruments are clean.  Staff should also perform routine quality checks of the instruments themselves for cleanliness. Therefore it is imperative that cleaning verification testing is also done on the instruments themselves. In additional cleaning verification test should be done on items that have been manually cleaned.

There are many commercially available products that can be used to evaluate the results of the cleaning process (e.g., protein, carbohydrate, adenosine triphosphate) on devices that have been mechanically or manually cleaned. The Association for the Advancement of Medical Instrumentation (AAMI) provides a list of available in-use tests to assess efficacy of cleaning of medical devices in ST79 Comprehensive guide to steam sterilization and sterility assurance in health care facilities, Table D.1.

The first step and the most common method is a visual inspection, usually involving the use of a lighted magnifying glass. However, visual inspection alone may not be sufficient for assessing the efficacy of cleaning processes.  Residual organic soil may still be present even though the device “looks clean.” Furthermore, visual inspection alone is not possible for the inner components of devices that have lumens (e.g., laparoscopic instruments, flexible endoscope channels). Internal channels of flexible endoscopes or other lumened devices may be inspected using an endoscopic camera or borescope, which penetrate the lumen and allow for improved visual inspection.

As part of a quality improvement process the efficacy of both manual and mechanical cleaning processes should be monitored and documented on an ongoing, periodic basis.
 Sterilization cannot happen unless the cleaning process is successful.  SPD must verify mechanical and manual cleaning efficacy and implement a quality system that includes manual and mechanical routine cleaning verification tests and documentation of the results.


  1. ST79 – Comprehensive guide to steam sterilization and sterility assurance in health care facilities, ANSI/AAMI ST79:2010 & A1:2010 & A2:2011 & A3:2012 & A4:2013
  2. Guidelines for Sterilization. In: Guidelines for the Perioperative Practice. Denver, CO: AORN, Inc; 2017
  3. Guidelines for Cleaning and Care of Surgical Instruments. In: Guidelines for the Perioperative Practice. Denver, CO: AORN, Inc; 2017