Why Your Accessory Has No Clinical Evaluation File

Written by HATEM RABEH, MD, MSc Ing

Your Clinical Evaluation Expert And Partner

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This scenario repeats across submissions. The assumption is simple and wrong: accessories don’t need the same clinical evaluation rigor as the main device. But MDR Article 2(2) is clear. An accessory is a device. And Article 61 applies to devices.

The confusion comes from habit. Under the directives, accessories often received lighter documentation. Companies wrote brief justifications, sometimes just technical descriptions. Notified Bodies varied in how they assessed these. Some accepted minimal documentation. Others requested more but not systematically.

MDR removed that flexibility. The regulation defines clinical evaluation requirements for all devices. No exception clause for accessories. No lighter pathway mentioned. Yet manufacturers still treat accessory clinical evaluation as an afterthought.

What the Regulation Actually Requires

Article 61(1) states that manufacturers shall specify and justify the level of clinical evidence necessary to demonstrate conformity. This applies to the device. An accessory, by definition under Article 2(2), is a device intended specifically by its manufacturer to be used together with another device.

The clinical evaluation must demonstrate safety and performance. For an accessory, this means demonstrating that it performs its intended purpose without introducing unacceptable risks when used with the device it accompanies.

MDCG 2020-13 on clinical evaluation provides the framework. It does not carve out accessories. The guidance describes how to establish clinical evidence. How to conduct literature searches. How to appraise data. How to analyze it. These steps apply regardless of device complexity.

Where manufacturers stumble is in assuming that because an accessory seems simple, the answer is obvious. It is not obvious to a reviewer. And obviousness is not evidence.

The Gap Between Practice and Expectation

In most submissions I see, the accessory documentation follows a pattern. A brief technical description. Material biocompatibility testing results. Perhaps a reference to a harmonized standard. Then a statement concluding that clinical evaluation is not applicable or that technical documentation suffices.

This fails on multiple levels.

First, it confuses technical documentation with clinical evaluation. Technical files contain design specifications, test results, risk management outputs. Clinical evaluation analyzes clinical data to demonstrate that the device achieves its intended clinical benefits and that known and foreseeable risks are minimized and acceptable.

Second, it assumes that biocompatibility and electrical safety testing replace clinical evaluation. They do not. These tests are inputs to risk management. They inform the benefit-risk determination. But they do not demonstrate clinical performance.

Third, it ignores that accessories often directly affect clinical outcomes. A sensor cable that introduces signal noise affects diagnostic accuracy. A battery that depletes unpredictably affects device availability during critical moments. A mounting bracket that fails affects procedural safety.

The Notified Body reviewer then raises a non-conformity. The manufacturer must respond. Often, they argue that the accessory is too simple to require clinical evaluation. The reviewer points to the regulation. No exception exists. The manufacturer then scrambles to build a clinical evaluation retrospectively.

This creates delay. It also creates poor documentation. Clinical evaluation built under pressure rarely meets the standard expected. Literature searches become superficial. Appraisal lacks depth. The analysis does not genuinely assess the evidence. It becomes a compliance exercise rather than a scientific assessment.

What a Proper Accessory Clinical Evaluation Contains

A conformant clinical evaluation for an accessory follows the same structure as for any device, adapted to the specific situation.

It begins with scope definition. What is the accessory? What is its intended use? With which device is it used? What are the clinical claims? Even for accessories, there are clinical claims. A cable claims to transmit signals without degradation. A stand claims to position a device safely. A battery claims to provide power reliably. These are clinical claims because they affect clinical use and outcomes.

Next comes the clinical development plan. What data is needed to demonstrate those claims? For accessories, this often includes device-specific performance testing, usability data, real-world use data, and literature on similar accessories.

Then the literature review. This is not a formality. The search must identify publications on the accessory type, on failures or incidents, on use conditions. The appraisal must evaluate whether the literature provides relevant evidence. The analysis must integrate findings with device-specific data.

Device-specific data for accessories often comes from verification and validation testing. This is where technical and clinical documentation intersect. Test reports showing signal fidelity, mechanical durability, or functional performance under use conditions provide clinical evidence. But they must be presented and analyzed as clinical evidence, not just listed as test results.

Post-market data matters for accessories. Complaints, field actions, vigilance reports. These provide evidence of real-world performance. If the accessory has been on the market, even under a previous regulatory framework, that data must be analyzed.

Finally, the benefit-risk determination and conclusions. What benefits does the accessory provide? What risks exist? Are risks acceptable given the benefits? Is the clinical evidence sufficient? This analysis must be explicit and justified.

Why This Matters More Than Manufacturers Realize

The practical consequence of inadequate accessory clinical evaluation is not just regulatory delay. It is a systemic weakness in the device’s overall evaluation.

Accessories are part of the device system. They affect performance. They contribute to risk. A main device with thorough clinical evaluation paired with an accessory lacking proper evaluation creates a gap in the overall safety and performance demonstration.

Notified Bodies increasingly scrutinize this. The expectation has shifted. Reviewers now routinely request full clinical evaluation reports for accessories. Some Notified Bodies require separate CERs. Others accept integrated evaluation within the main device CER but demand complete sections addressing each accessory.

Manufacturers who continue with minimal accessory documentation face repeated non-conformities. This pattern signals to the Notified Body that the manufacturer does not understand clinical evaluation requirements. It affects the overall assessment of competence and quality of documentation.

There is also a post-market surveillance implication. Accessories without proper clinical evaluation lack a baseline for PMCF. How do you confirm continued safety and performance if you never established what data demonstrates safety and performance? PMCF plans for accessories often fail because the initial clinical evaluation was never adequate.

How to Build This Right From the Start

The solution is not to write more pages. It is to conduct actual clinical evaluation for accessories.

Start during device development. When defining the device system, identify each accessory. Define its intended use and clinical claims. Plan what data will demonstrate those claims. This becomes part of the clinical development plan.

Conduct literature searches for each accessory type. A cable requires searching literature on signal transmission, cable failures, biocompatibility of connector materials, user errors in cable handling. A battery requires searching literature on battery reliability, failure modes, user interaction with battery replacement or charging.

Appraise the literature for relevance and quality. Analyze what it tells you about risks and performance. Identify gaps in knowledge. Determine what device-specific data must fill those gaps.

Generate that device-specific data through testing and validation. Document it properly. Include clinical context in test protocols. For example, if testing a sensor cable, test under conditions that simulate clinical use. Include interference, movement, repeated connection and disconnection.

Integrate post-market data as it becomes available. Complaints about accessories often reveal real-world failure modes not anticipated during design. This data must feed into the clinical evaluation and into risk management.

Write the clinical evaluation report for accessories with the same rigor as for the main device. Use the same structure. Answer the same questions. Provide the same level of analysis. The report may be shorter because the accessory is simpler. But it must be complete.

The Reality Check

I understand the resistance. Manufacturers see accessories as low-risk, standard components. Why invest time in extensive evaluation?

The answer is that the regulation does not differentiate. MDR requirements apply. Notified Bodies enforce them. The path of least resistance is not to minimize documentation. It is to conduct proper evaluation from the beginning.

This does not mean every accessory requires years of clinical trials. It means every accessory requires a systematic evaluation of available evidence to demonstrate safety and performance. For many accessories, that evidence comes primarily from technical testing and literature. But it must be gathered, appraised, and analyzed properly.

The manufacturers who succeed in this area treat accessories as devices from the start. They apply the same clinical evaluation methodology. They produce documentation that withstands review. They avoid the non-conformities and delays that plague others.

The question is not whether your accessory needs clinical evaluation. The regulation already answered that. The question is whether your organization is prepared to conduct it properly.

Most are not. The gap is widening between regulatory expectation and industry practice. Closing that gap requires changing how accessories are perceived and documented. It requires recognizing that a cable is a device, a stand is a device, a battery is a device. And devices require clinical evaluation under MDR.

This shift in approach separates manufacturers who will navigate MDR successfully from those who will continue to face regulatory barriers. The choice is straightforward. Treat accessories as documentation footnotes and face repeated challenges. Treat them as devices requiring proper evaluation and build submissions that progress smoothly.

The oversight is understandable given past practice. But it is no longer acceptable under current requirements. Reviewers expect complete clinical evaluation for accessories. Manufacturers must deliver it.

Peace,
Hatem
Clinical Evaluation Expert for Medical Devices
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