ISO 10993 is the cornerstone standard for assessing the biological safety of medical devices. By focusing on risk assessment rather than prescriptive testing, it provides a flexible framework for evaluating device materials in their final form. This guide delves into the scope, challenges, updates, and practical applications of ISO 10993, drawing insights from expert Jeremy Tinker.

Understanding the Scope of ISO 10993

ISO 10993 is designed to evaluate the biological risks associated with medical device materials. The standard is built on three key pillars:

1. Risk Assessment: A comprehensive evaluation tailored to the device’s materials and how they interact with the human body.
2. Categorisation of Devices: Grouping devices by their level of patient contact and potential risk.
3. Gap Analysis: Identifying existing data, evaluating its sufficiency, and determining additional testing or information needs.

Unlike traditional standards, ISO 10993 avoids a one-size-fits-all approach. It doesn’t prescribe specific tests but instead emphasises the importance of toxicological risk assessment and biocompatibility evaluation.

Dual Evaluation Pathways

ISO 10993 employs two complementary approaches to assess biological safety:

1. Toxicological Risk Assessment:
   This process identifies toxicological hazards associated with device materials. It evaluates risks using chemical analysis, focusing on exposure to potentially harmful substances. This aligns with the broader risk management principles outlined in ISO 14971.
2. Biocompatibility Assessment:
   This pathway examines the body’s response to device materials, particularly in tissues and blood. It is critical for implants or devices with prolonged contact with internal body systems. The goal is to ensure compatibility and minimise adverse reactions.

Challenges and Misinterpretations in Applying ISO 10993

Although comprehensive, ISO 10993 is often misinterpreted, leading to compliance challenges for manufacturers. Jeremy Tinker highlights some of the most common pitfalls:

1. Misconceptions About Testing

Many manufacturers mistakenly view ISO 10993 as a checklist of tests rather than a flexible, risk-based process. This misunderstanding stems from its historical evolution, where early standards focused on testing novel materials. While revisions in 2018 addressed these issues, some still perceive the standard as requiring exhaustive testing for all devices.

2. Inadequate Expertise

Clause 4 of ISO 10993 mandates that evaluations be conducted by knowledgeable professionals. However, a global shortage of experts in toxicology, material science, and risk management often leads to poorly executed assessments. For example:

• Silver Misuse: Antimicrobial silver was improperly applied in certain devices, leading to unexpected risks.
• Aluminium Leaching: Insufficient toxicological evaluations allowed harmful levels of aluminium to leach from devices.

These examples underscore the importance of involving experienced professionals in the evaluation process.

3. Over-Testing

Overly cautious or misinformed evaluations often result in unnecessary studies, such as chemical characterisation or implantation tests that add no value. These not only waste resources but can yield problematic results that complicate regulatory approval.

Recent Updates to ISO 10993

ISO 10993 is continually updated to reflect advances in science and address industry feedback. Significant changes include:

2018 Revision to Part 1

• Introduced a strong emphasis on data-driven evaluations.
• Clarified the importance of chemical and physical information as the starting point for risk assessment.
• Rejected the notion of ISO 10993 as a recipe for testing, focusing instead on tailoring evaluations to the specific device.

Part 18 (2020): Chemical Characterisation

• Introduced a stepwise approach, starting with existing data and only generating new information as needed.
• Clarified when chemical analysis of extracts is required.
• Explained the concept of biological equivalence, critical for demonstrating compliance under the European Medical Device Regulation (MDR).

Part 17 Revision:

• Shifted focus to toxicological risk assessment, incorporating modern toxicology practices.
• Aligned closely with ISO 14971, ensuring biological evaluation fits seamlessly into broader risk management processes.
• Renamed the standard to reflect its updated scope.

These changes are reshaping how manufacturers approach biological safety, with a clear emphasis on reducing unnecessary testing and improving clarity around risk management.

Best Practices for Compliance

Achieving compliance with ISO 10993 requires a structured, scientifically robust approach. Jeremy Tinker offers three key recommendations for manufacturers:

1. Start Early

Begin your biological evaluation plan (BEP) at the earliest stages of product development. Use a gap analysis to identify existing data and determine additional testing or information needs.

2. Select Data Sets Thoughtfully

Avoid unnecessary or irrelevant testing by clearly defining data gaps and aligning studies with risk assessment goals. Poorly planned studies can lead to unexpected or unhelpful results, particularly in chemical characterisation or implantation tests.

3. Define Acceptability Criteria

Establish clear benchmarks for safety and risk acceptability in advance. This ensures that test results can be evaluated efficiently and effectively.

The Role of Expertise in ISO 10993

Successful compliance hinges on the involvement of knowledgeable and experienced professionals. These experts:

• Interpret toxicological data.
• Conduct nuanced risk assessments.
• Ensure evaluations are scientifically sound and meet regulatory expectations.

Without qualified personnel, manufacturers risk overlooking critical hazards or misinterpreting results, potentially leading to regulatory delays or product recalls.

Looking Ahead: The Future of ISO 10993

ISO 10993 is expected to continue evolving. Proposals to refine Part 1 further underscore the need for optimisation. Manufacturers and regulatory bodies alike are encouraged to stay informed of updates to ensure their processes remain state-of-the-art.

Conclusion: Why ISO 10993 Matters

ISO 10993 is not just a compliance tool—it’s a framework for delivering safer, more effective medical devices. By embracing its risk-based approach, leveraging expertise, and staying aligned with updates, manufacturers can confidently navigate the complexities of biological evaluation.

The key to success lies in understanding the principles, starting early, and involving the right expertise. With ISO 10993 as a guide, the path to safer medical devices becomes clearer.

Watch the interview on ISO 10993 (biological evaluation of medical devices) below.