Declaration of Conformity: Annex IV Requirements and Common Errors

What the DoC is — and what it is not

The Declaration of Conformity is the manufacturer's formal statement that the device meets the applicable requirements of MDR. It does not demonstrate conformity — your technical documentation does that. The DoC is the endpoint, the signature on work already done. This distinction matters because teams sometimes treat the DoC as the deliverable rather than the evidence it summarises.

The DoC must be issued by the manufacturer, not the Authorised Representative, distributor, or importer. For a manufacturer outside the EU, the AR can assist in drafting, but the responsible person signing the DoC is the manufacturer's own named signatory. If that person changes after the DoC is issued, the DoC should be reviewed and reissued.

Annex IV — element by element

Annex IV lists the required elements of the DoC. Going through them in order:

Name and registered place of business of the manufacturer — straightforward, but the legal name must match the registration documents and EUDAMED registration. Abbreviated trading names or holding company names are a common error.

A single EU declaration of conformity is drawn up for all devices covered — a single DoC can cover multiple models in a device family, but all devices listed must be covered by the same conformity assessment. You cannot aggregate devices from different conformity assessment routes into one DoC.

Name, reference and edition of the harmonised standards applied — this is where most errors occur. See the standards list section below.

Where applicable, the name and identification number of the Notified Body — required for Class IIa, IIb, and III devices and any Class I device with NB involvement. The NB identification number is the four-digit number assigned by the Commission. Do not use the NB's own internal reference number.

The conformity assessment procedure followed — specify the Annex reference (Annex IX, X, or XI). If you followed a combined route (e.g., Annex IX Section 4 for manufacturing quality assurance with Annex X for type examination), both must be cited.

The date of issue, duration, and expiry date — the DoC is valid for the period covered by the conformity assessment. For NB-certified devices, the DoC expiry is typically aligned to the NB certificate expiry.

Name and signature of the responsible person — this must be an identified natural person, not a role or title. The signatory is the Person Responsible for Regulatory Compliance (PRRC) or another person designated by the manufacturer with authority to commit the organisation.

The standards list problem

The harmonised standards section is the most common source of errors in Declarations of Conformity — and the most common audit finding. The problem has two forms:

Form 1 — Standards included that were not actually applied. Teams copy a list of relevant harmonised standards from a template or from a competitor's DoC and include everything that might apply to their device type. The DoC then claims conformity with standards the manufacturer did not actually use during development and testing. An auditor who asks for evidence of conformity with a listed standard and finds none has grounds for a major nonconformity. Only list standards you can produce evidence for.

Form 2 — Standards that were applied but in superseded editions. Harmonised standards are periodically updated, and the Official Journal lists which edition is current. If you applied an older edition, you need to be able to demonstrate that the new requirements introduced in the updated edition were either not applicable to your device or were addressed through other means. Simply listing the current edition when you actually used the previous one is inaccurate.

The correct approach: your DoC standards list should come directly from your technical file. The risk management file, design verification and validation records, and test reports should reference specific standard editions. The DoC then reflects exactly those editions. Any deviation from the current harmonised standard requires justification in the technical file.

What changes to the device mean for the DoC

The DoC must be kept current. If your device changes in a way that affects conformity — new materials, modified intended purpose, changes to software functions, changes to sterilisation — you need to assess whether the existing DoC remains accurate and whether a new conformity assessment is needed.

Under Article 10(9), the DoC must be updated following any significant change to the device. For NB-certified devices, significant changes must be submitted to the NB, and the NB determines whether a new or supplementary certificate is required. A DoC that refers to an NB certificate that has since been superseded by a new certificate version is not current.

One thing that catches teams off guard: changes to harmonised standards — where a previously listed standard is updated with new requirements — can also trigger a DoC review even if the device itself has not changed. Keep a watch on the Official Journal updates for the standards you have cited.

Before you sign: a practical checklist

Before issuing or reissuing a DoC, confirm:

• The manufacturer name and address matches EUDAMED registration exactly
• Every device listed is covered by the same conformity assessment
• Every standard on the list has supporting evidence in the technical file
• Standard editions match what was actually applied, with justification for any deviations
• The NB name, number, and certificate reference are current
• The conformity assessment annex cited matches what was actually done
• The signatory is an identified person with documented authority
• The date of issue reflects when the conformity assessment was completed

The DoC is a legal document that will be requested by Competent Authorities, customs, and customers. Getting it wrong is not just an audit finding — it can create market access problems and undermine your CE marking.