Tests within the validation of processing instructions for medical devices
(acc. to DIN EN ISO 17664)

Manufacturers and distributors of medical deviceswhich are designed for reuse, must provide information for their pro­ducts and instructions for processing of the products in order to guarantee the clean processing results required for pa­tient safety. These also include some medical devices for single use which are sold non-sterile but are designed for use in a clean, disinfected and, if necessary, sterile condition.

As per DIN EN ISO 17664 at least one automated process must be described in these instructions, unless the medical device is not suitable for such a process. In this case a manual process must be described. These instructions must con­tain specifications for cleaning (with precleaning as applicable), disinfection and sterilization of the products. As per the specification in DIN EN ISO 17664 these product-related instructions have to be validated, i.e. laboratory tests must be carried out to verify that the specifications in the instructions genuinely result in the product having a cleanliness condi­tion with which it can be safely re-used on patients.

The tests within the validation of the instructions is performed by applying a defined test contamination to the product (e.g. a mixture of blood and bacteria), with areas of the product which are difficult to access being afforded particular attention, and subsequently cleaning and disinfecting the product follows exactly in accordance with the specifications in the product-related instructions. The specifications of the instructions must be so exact that as far as possible the party performing the test cannot influence the results.

The success of the cleaning step is tested by measuring the reduction of protein contamination on the product. The success of disinfection can be determined from the reduction of a test organism suitable for testing disinfection.

Test procedure

Contamination Inoculation of the product with a test contamination (e.g. mixture of blood and bacteria)
Precleaning If applicable, manual precleaning of the product before automated processing
Processing Manual or automated (washer-disinfector)
Assessment of cleaning Visually clean; residual protein < 100 g, reduction of the bioburden by at least 2-4 log steps
Bewertung der Desinfektion Determination of residual bioburden disinfection