Choosing Your Conformity Assessment Route Under EU MDR

The route follows the class — but the workload varies enormously

Once you know your device class, your conformity assessment route is largely determined. What varies is the depth of scrutiny: a Class I self-declaration is entirely within your control, while a Class III Annex IX (full QMS plus product scrutiny) involves your Notified Body at multiple stages. The gap in effort and cost between these is substantial, and many manufacturers underestimate what the middle ground — Class IIa and IIb — actually requires.

The conformity assessment routes are defined in Article 52 and reference the Annexes. Understanding which Annex applies to you is not optional background reading — it directly defines your obligations, timelines, and what your Notified Body will be scrutinising.

Class I: self-declaration, but not straightforward

Class I devices — non-sterile, with no measuring function, and not reusable surgical instruments — are self-declared. The manufacturer draws up a Declaration of Conformity and applies the CE mark without involving a Notified Body. This sounds simple, but the technical documentation requirements are the same. You still need a complete Annex II technical file, a conformity assessment procedure under Annex IV (for Class I), clinical evaluation, PMS plan, SSCP, and a registered responsible person in the EU. Notified Bodies are not involved, but market surveillance authorities can — and do — audit Class I devices. "We self-declared" is not a defence if the documentation is absent or inadequate.

Class Is (sterile), Class Im (measuring function), and Class Ir (reusable surgical instruments) require Notified Body involvement for those specific aspects, even though the overall class is still I. A lot of Class I manufacturers are caught off guard by this when they check whether their device has a sterile variant or a measuring function.

Class IIa: QMS certification plus technical documentation assessment

Class IIa devices require Notified Body involvement. The standard route is Annex IX (QMS assessment) combined with Annex II (technical documentation sampling) or Annex III (for custom-made devices). Alternatively, manufacturers can use Annex XI (product verification) combined with Annex II or III.

Under Annex IX, your Notified Body audits your quality management system and then performs a technical documentation review. For Class IIa, this review is typically a sample-based assessment — not every device in your portfolio is reviewed in full. This is where teams sometimes relax too early. The sampling does not mean other devices are not scrutinised — it means the Notified Body selects devices at their discretion, and they tend to pick the ones that present the most complexity or risk.

Class IIb: the scrutiny level increases significantly

Class IIb follows the same route structure as IIa (Annex IX + II/III, or Annex XI + II/III), but the scrutiny is deeper. The technical documentation assessment for Class IIb is not sample-based in the same way — the Notified Body is expected to assess at least one representative device per generic device group. This means more technical file reviews, more questions, and more clinical scrutiny.

One thing that catches a lot of teams off guard at Class IIb: the clinical evaluation requirements are substantially more demanding than for Class IIa. The bar for demonstrating clinical benefit and acceptable benefit-risk is higher, and the PMCF requirements are more intensive. If your Class IIb device is relying heavily on equivalence-based clinical data rather than clinical investigations, expect detailed questions from your Notified Body about the basis for equivalence.

Class III: the most demanding route

Class III devices use Annex IX with product verification scrutiny, or Annex X (type examination) combined with Annex XI. The key distinction at Class III is that the Notified Body must perform a clinical evaluation consultation procedure — the scientific committee process defined in Article 54 and Annex IX Section 5.1. This adds a layer of review by independent clinical experts and can significantly extend your certification timeline.

Manufacturers new to Class III are often surprised by two things: the timeline (plan for 18–24 months from Notified Body application to certification as a realistic baseline, not a target), and the depth of clinical data requirements. Reliance on equivalence for Class III devices is almost never accepted — you will generally need data from clinical investigations unless you can demonstrate direct access to data from an equivalent manufacturer's device.

Choosing between Annex IX and Annex X + XI

For Class IIb and III, manufacturers have a formal choice between the Annex IX route (QMS assessment) and the Annex X + XI route (type examination and product verification). In practice, almost all manufacturers use Annex IX. The Annex X route is suited to situations where a QMS approach is not practical — essentially legacy device situations or one-off productions. If you are building your compliance system for an ongoing commercial product, Annex IX is the route to discuss with your Notified Body from the start.

Timelines and capacity planning

Notified Body capacity is not unlimited. Application-to-certification timelines have extended significantly since MDR came fully into force. Class IIa devices should plan for 12–18 months; Class IIb and III should plan for 18–24 months or more. These are realistic ranges based on current market experience, not guarantees. Your Notified Body will give you their current estimates — take those seriously and build them into your project planning.