Medical Device Disinfection Validation

Medical Device Disinfection Validation


Microchem Laboratory routinely conducts medical device disinfection validation studies.  If your company would like to validate instructions for reprocessing or disinfection, please contact us for a quote.

We routinely conduct studies of the following type:

These studies are a critical part of the development of any reusable medical device.  We provide a summary of the pertinent FDA guidance below:

Testing Overview

A disinfection validation is an experiment that determines the efficacy of a disinfection procedure on a medical device. Prior to use, all test devices should be worn in with simulated use to properly assess the disinfection procedure as it would perform against actual in-use devices.

The device is first inoculated with the test microorganism determined by the Study Sponsor. This varies based on the desired disinfection level (Low, Intermediate, or High-level disinfection), largely determined by the kind of contact the device makes with patients. For submission to any regulatory agencies, each test microorganism needs to be evaluated independently, as pooling the test microorganisms can lead to competitive inhibition, resulting in misleading results. Inoculum is applied to sites that would be considered ‘worst-case’. These sites are those that will experience more handling during use or sites that are hard to reach such as crevices. Once the test device has been inoculated, it may be handled to emulate regular use. This can involve twisting dials, pressing on a touchpad, turning a switch on, or any number of actions. The emulation of normal use is to allow inoculum to access areas in a manner typical for the device, allowing for an accurate measure of the efficacy of the disinfection procedure.

Once the inoculum is dry, the disinfection procedure is performed. This procedure varies from test to test depending on what the Study Sponsor provides and can vary greatly. After the test device has undergone disinfection, the extraction process begins. The extraction process involves taking a combination of wet and dry sterile swatches/swabs and wiping down the target sites of the device. As those sites are harvested, the swatches/swabs are placed into a container of recovery fluid so that each site may be evaluated independently. At the request of Study Sponsors, this can be altered to pool all sites into one volume to evaluate the efficacy of the procedure against the whole device. Evaluation of a pooled volume does not provide insight into how well specific areas are being disinfected but can be a cost-efficient way to evaluate a disinfection routine.

During experimentation, controls are harvested as well. A positive control is performed by harvesting an inoculated test device that has not received the relevant cleaning. The negative control is performed by extracting from a device that has not been inoculated but has received cleaning.

The recovery fluid samples for each extraction site are then diluted appropriately and the dilutions plated in duplicate. These dilutions are meant to cover a wide array of dilutions and provide plate counts that can be used to adequately assess the efficacy of the disinfection procedure against the target microorganism. The plates are incubated as appropriate for the microorganism with sterility plates, meant to test the sterility of all media/materials used in testing. After incubation, colony-forming units on the plates are counted and the values are compared to the success criteria stated in the test protocol. All sterility plates are assessed to ensure no systemic contamination was derived from contaminated media.

Microchem Laboratory routinely conducts medical device disinfection validation studies. If your company would like to validate instructions for reprocessing or disinfection, please contact us for a quote.