Did you know an FDA Class II medical device could be immediately considered as a high-risk Class III device under European Union regulations?
For medical device manufacturers pursuing global market access, few decisions are important as determining your product’s regulatory class. This is crucial for defining your entire journey to compliance.
The classification assigned to your device determines the volume and rigor of the clinical data and technical documentation you must provide. It will determine the cost of Notified Body fees. Ultimately, this will impact how long it will take to get your product to market.
The challenge to a US manufacturer looking to sell their device in Europe is that the classification rules in the U.S. and EU are completely different, with no guaranteed match between the two systems. What looks like a simple Class II clearance in the U.S. may trigger complex Class IIb requirements in the EU, drastically increasing your required clinical evidence. This regulatory distinction tends to be one of the major sources of delay, but with the right guidance, it can be accurately managed with precision.
As an example, many U.S. manufacturers mistakenly assume that because their device achieved FDA clearance via “substantial equivalence” to a competitor’s product, the same logic applies in Europe. However, the EU MDR requires manufacturers to have access to the full technical documentation of any device they claim equivalence to, data that competitors are often unwilling to share. When a Notified Body rejects these dossiers, the result is an unsuccessful launch, forcing companies to stop operations and begin expensive, multi-year clinical trials from scratch just to prove what they thought was already established.
The US FDA System: Risk-Based Structure
The regulatory framework enforced by the U.S. Food and Drug Administration (FDA) is built on a straightforward, risk-based structure. Its simplicity, especially when compared to the EU’s system, is often what makes the EU transition so challenging for manufacturers.
The FDA classifies devices into three main categories based on the risk they pose to the patient and user:
| FDA Class | Class I | Class II | Class III |
|---|---|---|---|
| Risk Level | Low Risk | Moderate Risk | High Risk |
| Description | Subject to General Controls only. These devices typically pose the lowest risk and are often non-life-sustaining. | Subject to General and Special Controls. Special Controls may include performance standards, post-market surveillance, and guidance documents. | Devices that are life-sustaining, life-supporting, or pose a significant potential risk of illness or injury. |
| Example Device | Tongue depressors, elastic bandages, some manual surgical instruments. | Infusion pumps, most diagnostic ultrasound devices, surgical drapes. | Implantable pacemakers, HIV diagnostic tests, heart valves. |
| Required Regulatory Evidence | Registration/Listing, QSR (no premarket review for most). | 510(k) Premarket Notification (The most common pathway, relying on a Predicate Device). | PMA (Premarket Approval), which requires extensive clinical data. |
The key distinction of the FDA system, particularly for the 510(k) Premarket Notification, is its reliance on precedence. To achieve clearance via 510(k), the company has to demonstrate Substantial Equivalence (SE) to a legally marketed, existing device, which is generally referred to as the predicate.
This means demonstrating that the new device is as safe and effective as the predicate device, as defined in the regulations, specifically 21 CFR § 860.7. This approach creates a clear, precedent-based approach for market entry based on similarity to devices already on the market.
For truly innovative devices that lack a predicate, manufacturers must pursue the De Novo Classification Request. This pathway allows a novel, low-to-moderate risk device to establish a new classification regulation (Class I or II) and, importantly, become a predicate for future similar devices. Conversely, high-risk devices with no equivalence are required to undergo a full PMA (Premarket Approval).
This entire framework is defined by the question, “How does this device compare to those which are already on the U.S. market?” The efficiency of this comparison is a major benefit, but it also creates the fundamental difference with the EU.
The EU MDR System: Rule-Based Structure
If the FDA system is about precedent (comparing your device to an existing one), the European Union’s Medical Device Regulation (MDR) is about prescriptive rules.
Manufacturers must first determine the intended use and then systematically check their device’s characteristics against the 22 rules defined in MDR Annex VIII.
Navigating the 22 Rules of Annex VIII
Rather than relying on precedence, the MDR requires manufacturers to systematically navigate 22 rules. These rules are categorised into four groups to ensure no device is overlooked:
- Rules 1–4 (Non-invasive devices): Covers everything from simple bandages to devices used for the channelled administration of body fluids.
- Rules 5–8 (Invasive devices): Classifies products based on how they enter the body and for how long, such as surgical instruments or long-term implants.
- Rules 9–13 (Active devices): Focuses on devices requiring an external power source, including diagnostic imaging and software.
- Rules 14–22 (Special rules): Covers specific categories like contraceptive devices, disinfectants, and those incorporating animal tissues.
If a device meets multiple rules, the one resulting in the highest classification always applies.
The MDR expands the classification system to four primary classes:
| MDR Class | Class I | Class IIa | Class IIb | Class III |
|---|---|---|---|---|
| Risk Level | Low Risk | Moderate Risk | Moderate to High Risk | High Risk |
| Description | Non-invasive, non-measuring, non-sterile devices. Lowest general risk. | Devices that are generally non-invasive but have contact with the body for limited durations. | Devices that are implanted short-term, administer certain medicines, or have a significant impact on health. | Devices that are permanently implanted, sustain life, or carry the highest risk of irreversible deterioration or death. |
| Conformity Assessment Route | Manufacturer Self-Declaration (Annex II/III) | Quality Management System (QMS) audit plus Technical Documentation review (Annex IX/XI) | Comprehensive QMS audit and specific product assessment (Annex IX/X/XI) | Full QMS audit, batch verification, and extensive Clinical Evaluation Report (CER) review. |
| Notified Body Involvement? | No | Yes | Yes | Yes |
The difference lies in how the classification is reached. The MDR classification takes into consideration mainly the factors presented below:
- Invasiveness: Rules classify devices based on their contact and interaction with the body (e.g., body orifices, surgically invasive).
- Duration: Classification changes if the use is transient (under 60 minutes), short-term (1 hour to 30 days), or long-term (over 30 days). A short-term implant is Class IIa; a long-term implant is typically Class IIb or III.
- Active or Non-Active: Whether the device depends on an external power source (electricity, energy other than gravity). Active devices start at Class IIa or higher.
- Standalone Software as a Medical Device (SaMD): Rule 11 is the most notorious source of reclassification under the MDR. Software that was previously Class I or II in the U.S. now often jumps to Class IIa, IIb, or even Class III. The logic is based on the impact of a potential failure: if the software provides information used to make a decision that could lead to death or an irreversible deterioration of health, it is automatically Class III.
This methodical, rule-based approach means that simply knowing your device’s FDA class is not enough. You must restart the process using the MDR rules, a regulatory exercise that few U.S. manufacturers find difficult because it requires more than just a paperwork update. Most are set up for the FDA’s precedent-based model, which focuses on similarity to existing products. Transitioning to the EU means building a complete technical file and potentially conducting new clinical trials to meet the specific requirements of the 22 mandatory rules.
FDA vs EU MDR: 3 Critical Differences in Medical Device Classification
Bridging the gap between the FDA and EU MDR classification systems is not a simple translation exercise. It requires a fundamental shift in regulatory strategy. Here are the three most common differences that cause delays, increase costs, and lead to market access failure for unprepared manufacturers:
Difference #1: The Classification Mechanism
| FDA (U.S.) | EU MDR |
|---|---|
| Precedent-Based | Rule-Based |
| Relies on demonstrating Substantial Equivalence to a legally Predicate Device (the 510(k) pathway) | Relies on applying 22 mandatory Annex VIII rules based on the device’s characteristics (invasiveness, duration, etc.) |
Difference #2: Regulatory Review
The classification directly determines who grants market access:
- FDA: Market access approval is centralised. For Class II and Class III devices, the FDA is the sole decision-maker for clearance (510(k) or PMA).
- EU MDR: Market access is decentralised and involves Notified Bodies (NBs), private organisations audited and supervised by EU Member States. Class I devices are self-declared (no NB). All devices Class IIa, IIb, and III require a full audit and review by an NB.
Difference #3: High-Risk Areas
The MDR places a significantly higher regulatory requirements on two specific device categories, leading to a classification becoming higher.
If your device is SaMD or a reusable surgical instrument, you are almost guaranteed to be facing a more rigorous and costly conformity assessment in the EU than you did with the FDA.
Preparing for EU market entry
For a successful transition from the FDA’s precedent-based system to the EU MDR’s rule-based system, you must abandon the assumption that your risk profile translates directly.
The only way to avoid this expensive rework is to implement a dual-market regulatory strategy planned upfront, beginning with an accurate, defensible classification under MDR Annex VIII. Correct classification determines your entire development timeline, required resources, and ultimately, your speed to market.
Correctly classifying your device is not just the first step, it’s the most important step to securing your CE Mark and launching your medical device successfully in Europe.
Contact us to schedule your 15-minute assessment with our MDR experts and establish a clear strategy for your MDR classification.
