ISO17664:2017 notes that disinfection can be carried out concurrently with manual cleaning of a medical device but does not provide any additional guidance. On the other hand, FDA specifies that cleaning steps should be validated separately and independently from disinfection or sterilization steps3. ISO17664-2:2021 provides a bit more guidance for the simultaneous cleaning and disinfection of non-critical devices and states that ”The requirements for cleaning and disinfection are stated as separate clauses in this document. However, when the steps are concurrent, the requirements of both stages can be considered as one. In such cases removal of soil, a reduction in microorganisms and inactivation of viable microorganisms can be achieved as a result of the combination of applying the disinfecting agent and a physical action.“ Given that ISO17664-2:2021 is recognized by FDA, we deem it appropriate for manual cleaning and disinfection to be a one-step process for non-critical, non-patient contacting devices where the possibility of cross contamination is very low to minimal. That said, although a one-step cleaning and disinfection process is theoretically acceptable for non-critical devices, there are some practical considerations that will determine whether manual cleaning and disinfection can be combined. Semi-critical or critical devices should always have a separate cleaning and disinfection (and/or sterilization) validation to conform with FDA guidance but also due to the practical considerations outlined below.
Any product that will be used to perform cleaning and disinfection in a one-step process should be marketed for both processes (i.e. the label claim of the product must specify that it can be used for both cleaning and disinfection). Many products are marketed for cleaning or disinfection only and can therefore only be used for cleaning or disinfection, resulting in separate products, instructions, and validations for cleaning and disinfection. This is especially true for products intended for the cleaning and (high-level) disinfection of semi-critical and critical devices, which is one reason why validations for these devices will always be performed separately.
The endpoints required for the cleaning and disinfection validation
In addition to the intended chemical being suitable for both cleaning and disinfection, the instructions can only be combined in a one-step process when they can be validated as such. In practice, this means that instructions can only be combined in a one-step process when the cleaning is assessed with a visual inspection and the disinfection is intended to be low level. Other end markers or disinfection levels will result in the cleaning validation interfering with the disinfection validation or vice versa. For example, the presence of microorganisms added to assess disinfection could contribute to protein levels for the cleaning validation. Contrarywise , the soil used for the cleaning validation can interfere with disinfection validations when Mycobacterium is evaluated. The cultivation of Mycobacterium species such as M. terrae takes weeks on a general agar, which will result in contamination by the non-sterile soil that is used for the cleaning validations. In these cases, validations will have to be performed separately, prompting a separate cleaning and disinfection section in the IFU.
Instructions for the manual cleaning and disinfection of non-critical devices can be combined in a one-step process when the chemical used to clean and disinfect the device is marketed for both actions and when the required validation allows for the simultaneous assessment of cleaning and disinfection.
 ISO 17664:2017 Processing of health care products – Information to be provided by the medical device manufacturer for the processing of medical devices.
 ISO 17664-2:2021 Processing of health care products – Information to be provided by the medical device manufacturer for the processing of medical devices – non-critical medical devices
 FDA 2015 Reprocessing medical devices in health care stings: Validation methods and labeling – Guidance for industry and food and drug administration staff