The correct pH for instrument reprocessing

The correct pH-value for detergents formulated for decontaminating surgical instruments is a topic which attracts some debate between the manufacturers of the instruments themselves and the detergent manufacturers. Those involved with the production of stainless-steel surgical instruments would argue that there is a need to maintain pH neutral chemistry in order to preserve the lifespan and usefulness of the instruments, i.e. to prevent potential corrosion caused by acidic or alkaline chemical formulations. The alternative argument, and the one often presented by the manufacturers of the detergents, is that with careful research and development, formulations can be designed which are more effective than pH alkaline. The question is, who is correct?

Guidelines

In the US, the CDC published its recommendation on Cleaning, A Guideline for Disinfection and Sterilization in Healthcare Facilities (2008). It states: “Ensure that the detergents or enzymatic cleaners selected [for cleaning of patient-care devices] are compatible with the metals and other materials used in medical instruments.” The guidance goes on to say that: “For instrument cleaning, a neutral or nearneutral pH detergent solution commonly is used because such solutions generally provide the best material compatibility profile and good soil removal… Neutral pH detergent solutions that contain enzymes are compatible with metals and other materials used in medical instruments and are the best choice for cleaning delicate medical instruments, especially flexible endoscopes. Alkaline-based cleaning agents are used for processing medical devices because they efficiently dissolve protein and fat residues; however, they can be corrosive.”^1-4