Medical Device Safety Testing – MDR focus on material compatibility

Why do medical devices require material compatibility testing to be performed?

The EU Regulation 2017/745 (MDR) heavily focuses on the safety and performance of a medical device for the lifetime of the product to minimise risk as far as possible. As a result, there is growing emphasis on compatibility, risk of contaminants and verification of the cleaning, decontamination and sterilisation of a product based on its’ instructions for use (IFU) to facilitate safe reuse.

With medical devices testing (including disinfectants or sterilising devices) becoming more complex, the potential for negative interactions increases. Therefore, it is critical that medical device manufacturers select appropriate materials for its’ intended use to ensure optimal functionality, efficiency, compatibility, and reliability. This can reduce the likelihood of product recalls associated with device failures due to compatibility with cleaning practices.

What is the importance of material compatibility?

Medical device safety testing, including, cleaning, disinfecting and sterilising is an important component within healthcare settings to prevent infections. Medical device materials and active ingredients/concentrations used within disinfectants vary significantly between devices meaning manufacturers of both medical equipment and disinfecting/sterilising products must contribute to helping align protocols and reinforce patient safety.

Material incompatibility can lead to:

• Plastic fatigue such as cracks, scratches, and crazing, is one of the stress factors of materials (along with creep and weathering) which can impact the performance over time. Plastic fatigue is often caused by solvents within in a formula. Not only can it provide a reservoir for pathogens, protecting them from future cleaning but dependant on the medical device can also result in leaks, corrosion, or overall failure of a product.
• Discoloration can occur when a material is exposed to sunlight or heat once the protective coating is removed. Metals also experience this (staining) where deposits are tightly adhered to the instruments surface which can make it appear as a gold or rusty tint and can be caused by many factors including impure steam or replating of metals (which can also cause a rainbow-like appearance).
• Streaky or salty residues can be caused by surfactants and solvents, or dissolved solids and can be acidic or alkaline in nature. This can also be known as metal spotting where water mineral deposits, chemical residues, steam residues or poor soil removal can cause loose or semi-adherent deposits to be present on the surface of an instrument. These can usually be removable by wiping with clean damp cloth but can result in damage to the surface of the material.
• Corrosion can occur when acidic and alkaline disinfectants or residues left behind damage the surfaces of a material. This can even occur products or materials covered with protective paints and coatings. The rate of corrosion can be influenced by several factors including temperature, pH, and moisture/humidity.

Read more about what makes medical devices incompatible with infection prevention and control practices.

What aspects should manufacturers consider when determining compatibility?

While some aspects may not affect the functionality of a medical device, the manufacturer must consider the risk-benefit ratio of their product to determine an acceptable residual risk. As part of the risk management process the manufacturer of a medical device should consider the intended use of the product and what claims they want to make in order to produce a technical file with evidence to support compliance with the MDR. Within the IFU of a medical device, which is intended to be reused, it must include details on the cleaning, decontamination and sterilising processes required and identification of when the device should no longer be used e.g., signs of material degradation or maximum number of allowable reuses.

Some of the most common indicators which can be tested to provide either quantitative or qualitative data include:

• Visual changes including colour, opacity, whiteness, build-up of residue and overall visual appearance
• Changes in texture or components of a material including roughness, cracking, peeling, flaking, holes, or other changes in the surface
• Changes to organic characteristics such as strength, flexibility, and weight, resulting in the material becoming brittle or losing adhesive properties
• Loss of functionality resulting in the device not working as intended for example components such as the display no longer working, wires becoming exposed or total loss in function

What are the benefits of Test Labs TL Mark framework?

As a medical device manufacturer, you ‘own’ the surface area of your products that are deployed in hospitals and must ensure that all reasonable steps are taken to minimise the risk of those surfaces becoming a vector of transmission.

The TL Mark is a framework of IFU validation tests developed by and unique to Test Labs that enables products achieving TL Mark status to demonstrate compatibility with universally applied cleaning and disinfection processes.

The TL Mark framework will also demonstrate that you are committed to reducing the incidence of healthcare-acquired infection (HCAI) and can be relied on by healthcare organisations as a supplier of compliant, sustainable medical devices.