If harmonized standards are the well-known path to demonstrating MDR compliance, Common Specifications are their less-discussed but equally powerful cousin. Both serve the same fundamental purpose. Providing detailed technical criteria that, when followed, give you a presumption or demonstration of conformity with MDR requirements. But they work differently, come from different sources, and have different legal weight.
For startups, understanding Common Specifications matters because they can define mandatory requirements that go beyond what harmonized standards cover. Ignoring them is not an option.
What Are Common Specifications?
Common Specifications (CS) under MDR are detailed technical requirements adopted by the European Commission through implementing acts. They are defined in MDR Article 9.
The Commission can adopt Common Specifications in two scenarios:
Scenario 1: No harmonized standard exists for a specific General Safety and Performance Requirement (GSPR), or the existing standards are insufficient.
Scenario 2: There is a need to address public health concerns. Situations where waiting for the standard harmonization process would create unacceptable safety gaps.
Common Specifications can cover: - General Safety and Performance Requirements (Annex I) - Technical documentation requirements (Annex II) - Clinical evaluation and post-market clinical follow-up requirements - Requirements for specific device categories (such as Annex XVI devices)
How Common Specifications Differ from Harmonized Standards
The distinction matters and trips up many startups:
| Aspect | Harmonized Standards | Common Specifications |
|---|---|---|
| Who creates them | European Standardization Organizations (CEN, CENELEC, ETSI) | European Commission |
| Legal mechanism | Referenced in the Official Journal of the EU | Adopted through implementing acts |
| Compliance effect | Presumption of conformity with relevant GSPRs | Demonstration of compliance with relevant requirements |
| Can you deviate? | Yes, if you demonstrate equivalent compliance by other means | Yes, but you must demonstrate that your alternative provides at least an equivalent level of safety and performance |
| Mandatory? | Following them is voluntary (but creates presumption of conformity) | Effectively mandatory unless you can justify an alternative |
The practical difference is significant. Harmonized standards are a recommended path. Follow them and you get the benefit of a presumption of conformity. Common Specifications are closer to a mandate. You must follow them unless you can demonstrate that your alternative approach achieves at least the same level of safety and performance.
Tibor explains the difference this way: "A harmonized standard says 'if you follow this, we assume you are compliant.' A Common Specification says 'you must follow this, and if you want to do something different, you must prove it is at least as good.' For a startup with limited resources, trying to prove equivalence to a Common Specification is usually more work than just following the CS. The practical advice is: follow the Common Specification."
Currently Adopted Common Specifications
As of 2026, the European Commission has adopted Common Specifications in several areas:
Common Specifications for Annex XVI Devices
Commission Implementing Regulation (EU) 2022/2346 established Common Specifications for the product groups listed in Annex XVI. Devices with no intended medical purpose. These CS define risk management approaches, clinical evaluation requirements, and specific performance criteria for aesthetic and lifestyle devices.
Common Specifications for Reprocessing of Single-Use Devices
Addressing the requirements for healthcare facilities that reprocess single-use medical devices, which is permitted under MDR Article 17 in Member States that allow it.
Other Areas
The Commission has adopted or is developing Common Specifications for additional areas. The pipeline of CS development is ongoing, and new CS may be adopted that affect your device category.
How Common Specifications Affect Your Technical Documentation
When a Common Specification applies to your device, it affects your technical documentation in several ways:
The GSPR Checklist
Your GSPR checklist (the systematic mapping of Annex I requirements to the evidence demonstrating conformity) must reference applicable Common Specifications. For each GSPR covered by a CS, you should indicate: - That the CS applies - That you have followed the CS (or, if you have deviated, the justification for your alternative approach) - The specific evidence in your technical file that demonstrates compliance
Clinical Evaluation
If a Common Specification defines clinical evaluation requirements for your device type, your clinical evaluation must follow those requirements. This is particularly relevant for Annex XVI devices, where the CS defines how clinical evaluation must address safety in the absence of medical benefit.
Risk Management
Common Specifications may define specific risk management requirements beyond what ISO 14971 covers generically. For example, the Annex XVI CS includes product-specific risk considerations that must be addressed in your risk management file.
Labeling and Information
CS may include specific labeling requirements. Information that must be provided to the user beyond the general MDR labeling requirements in Annex I Chapter III.
The Deviation Question
MDR Article 9 allows manufacturers to deviate from Common Specifications, but only if they can demonstrate that their alternative solution provides a level of safety and performance that is at least equivalent.
In practice, deviating from a CS is difficult and risky:
- The burden of proof is on you. You must provide documented evidence that your approach is at least as good.
- Notified Bodies will scrutinize deviations. A deviation from a CS will draw additional attention during the conformity assessment. The NB will need to be convinced that your alternative is adequate.
- Market surveillance authorities may challenge deviations. Even after certification, authorities can question whether your deviation is justified.
For startups, the practical advice is clear: follow applicable Common Specifications unless you have a strong technical reason to deviate and the resources to defend that deviation. The compliance path through the CS is well-defined and accepted. The deviation path is uncertain and resource-intensive.
How to Stay Current with Common Specifications
Common Specifications are adopted through implementing acts, which are published in the Official Journal of the European Union. To stay current:
- Monitor the Official Journal for new implementing acts related to MDR Common Specifications
- Follow MDCG publications. The Medical Device Coordination Group often discusses upcoming CS before they are adopted
- Check with your Notified Body. They track CS developments as part of their designation requirements
- Subscribe to regulatory intelligence services. Several commercial services track EU regulatory developments for medical devices
For a startup, the most practical approach is to check for applicable CS at the start of your regulatory project and again before submitting to the Notified Body. CS are not adopted frequently, so a periodic check (quarterly or at key project milestones) is sufficient.
Common Specifications and the Innovation Challenge
There is an inherent tension between Common Specifications and innovation. CS codify specific technical requirements based on current knowledge and technology. Innovative devices may employ novel approaches that do not fit neatly into existing CS.
MDR acknowledges this through the deviation provision. If your innovative approach achieves equivalent safety and performance, you can deviate from the CS. But in practice, innovative startups face a higher regulatory burden because they must prove equivalence rather than simply following the established path.
Tibor's perspective: "The tension between standardization and innovation is real. Common Specifications are written for known technologies and known risks. When you bring something genuinely new, the CS may not fit. That is where the regulatory dialogue becomes critical. With the Notified Body, with the competent authority, sometimes with the MDCG itself. You need to engage early and explain your approach before submitting documentation that deviates from the CS."
Practical Checklist for Startups
When evaluating Common Specifications for your device:
- Identify whether any CS applies to your device type. Check the Commission's adopted implementing acts and the MDCG guidance.
- If a CS applies, obtain the full text. Read it carefully. CS are typically detailed and specific.
- Map the CS requirements to your device. Identify which specific provisions apply and which do not.
- Integrate CS requirements into your regulatory plan. Add them to your GSPR checklist, your clinical evaluation plan, your risk management plan, and your testing program.
- If you intend to deviate, document the justification early. Do not leave deviation justifications to the Notified Body review stage.
- Discuss CS applicability with your Notified Body. Include it in pre-submission discussions if there is any ambiguity.
The Bottom Line
Common Specifications are the European Commission's mechanism for setting binding technical requirements where harmonized standards are absent or insufficient. They are closer to mandatory than harmonized standards, and deviating from them requires substantial justification.
For most startups, the practical approach is straightforward: identify applicable CS, follow them, and document compliance. The CS provide a clear path. More defined than interpreting raw MDR text on your own, and more specific than general harmonized standards.
As the MDR matures and the Commission identifies more areas where specific technical requirements are needed, expect more Common Specifications to be adopted. Build regulatory monitoring into your operations so you are never surprised by a new CS that applies to your device.