By Alastair Fry, Head of Regulatory Affairs at Europlaz

When people talk about medical device development, the focus often lands on functionality, usability and clinical performance. Those things matter, of course. But from a regulatory and patient safety perspective, one area that should never be treated as an afterthought is biocompatibility testing for medical devices. In simple terms, biocompatibility is about understanding whether a device is biologically safe for its intended use, based on the materials it contains, the way it is used and the type of contact it has with the body. That assessment sits within a wider risk management process and is fundamental part of demonstrating that a device is suitable for market.

In my experience, one of the biggest mistakes teams can make is leaving biocompatibility too late. It is far better to consider it in good time, because the route you need to take depends on a number of important factors: what the device does, how it is used, whether contact is direct or indirect, how long that contact lasts, and what materials and processes sit behind the final product. If those questions are left until the end of development, the result can be delays, avoidable rework and a more difficult regulatory pathway, which is why early stages such as medical device feasibility and Design for Manufacture (DFM) matter so much.

A key point to understand is that biocompatibility testing for medical devices is not the same in every case. Some devices fall under the ISO 10993 series because they have direct or indirect contact with the body. Others, particularly devices involving breathing gas pathways, fall under ISO 18562. The correct route depends on how the device interacts with the patient and what biological risks need to be assessed, and it should sit within a broader framework of quality assurance for medical device manufacturing and documented regulatory control.

That is why intended use and patient conduct are so important from the outset. They provide the context for deciding what endpoints need to be addressed and what evidence is required to support biological safety. Even for relatively straightforward devices, biocompatibility still needs to be considered properly. At a minimum, there should be a clear rationale for the approach taken, whether that leads to testing, a scientific justification, or a combination of both. In practice, many devices need to consider endpoints such as cytotoxicity, sensitisation and irritation, while others may also require consideration, such as haemocompatibility, pyrogenicity, extractables and leachables, toxicological risk assessment or sterilisation residuals. What matters is that the route is based on the device’s real characteristics rather than assumptions.

Why planning matters in biocompatibility testing for medical devices

A strong biological evaluation starts with a plan. In regulatory terms, that means clearly defining what is being assessed, why it is being assessed, what information is already available and what gaps still need to be addressed. That planning stage matters because it helps avoid unnecessary testing, supports a more robust scientific rationale and gives all parties a clearer framework for decision-making. It also means there is less risk of heading down the wrong route and having to revisit the work later. It also sits naturally alongside medical device validation services, where documented evidence and structured process control become critical.

This is particularly important because biocompatibility is not only about the material in isolation. It is about the finished device and how that device will perform in use. Materials may already have data available, but regulators still expect manufacturers to consider how those materials behave when brought together in a final product, processed in a specific way and used in a real clinical setting. Biological evaluation therefore needs to reflect the device as a whole, not just a collection of parts, especially when moving towards medical device manufacturing at scale.

This lifecycle mindset is also reflected in the standards. The biological evaluation process is designed to consider risks from design and development through to use of the finished device, and to account for how the product may change over time. It is not simply a lab exercise. It is part of understanding the device in context and making sure that context is properly captured in the evidence base.

Why manufacturers benefit from practical support

For many manufacturers, especially those without extensive in-house regulatory resource, the challenge is not recognising that biocompatibility matters. The challenge is knowing where to start, what information to gather and how to structure the process in a way that stands up to review. That is often where practical support can make a real difference. The value is in understanding intended use, patient contact, materials, manufacturing methods and lifecycle considerations well enough to define the right route from the beginning, particularly at the feasibility and Design for Manufacture (DFM) stages.

At Europlaz, we see our role as helping customers make sense of that route. That can mean helping define requirements, making sure the right technical and manufacturing information is available, and coordinating with specialist external partners whose expertise lies in biological evaluation and testing. In my view, that is often the better approach. Specialist consultancies and test houses work in this area every day, and their knowledge is invaluable when it comes to making sure the work is compliant, defensible and aligned with current expectations. Europlaz’s strength is in combining that specialist input with practical manufacturing understanding.

My view: think about biocompatibility earlier

If there is one message I would emphasise, it is this: start thinking about biocompatibility testing for medical devices earlier than you think you need to. Ask the difficult questions at the start. What is the intended use? Who is the patient population? Is the contact direct or indirect? How long is that contact? What materials are involved? What processing or sterilisation methods could influence the biological profile? Those questions are not just regulatory admin. They shape the evidence pathway and can help prevent unnecessary problems later in development.

Ultimately early thinking creates a stronger foundation. It can reduce delays, improve decision-making and make the regulatory pathway clearer. Most importantly, it supports the central goal of biocompatibility work in the first place: making sure the device is safe for the people who will ultimately use it.

Closing thoughts

If you are developing a product and need help understanding the right route for biocompatibility testing for medical devices, Europlaz can support you in defining the key considerations early, gathering the right information and coordinating the specialist support needed to move forward with confidence. To explore the wider pathway, visit our services overview or learn more about medical device manufacturing

To discuss biocompatibility testing with one of our experts contact us.