Manufacturers on the Annex IX QMS conformity assessment route often assume their notified body reads every device's technical file before issuing or renewing a certificate. For most Class IIa and IIb devices, it doesn't. Annex VII, §4.5.2(a) of the MDR requires the notified body to draw up and keep a sampling plan for assessing technical documentation, and MDCG 2019-13 sets the working baseline at 15% of devices per category and generic device group — reviewed on a representative basis across the certificate's validity, not device by device.
Where the sampling obligation actually sits
The sampling requirement is easy to misplace, because the mechanic people reach for — Annex IX's QMS conformity assessment route — is not where the obligation is written. Annex IX, §2.3 describes the notified body assessing technical documentation for a representative sample of devices as part of that route, but the duty to build and maintain the sampling plan itself sits in Annex VII, the chapter governing what notified bodies must do structurally, not what manufacturers submit. That distinction matters operationally: the sampling plan is the notified body's instrument, built against its own designation scope and the categories and generic device groups it has defined for your certificate — not a document your quality system produces or controls.
What 15% actually means for your portfolio
The rate applies within each category and generic device group covered by the certificate, not as a flat slice of the whole portfolio. A manufacturer with several generic device groups under one notified body designation scope should expect the sampling plan to pull a representative subset from each group separately, which means a narrow, low-volume device family can sit for a full certificate cycle without its technical file being individually opened by the notified body at all. That is not a gap in the regulation — it is the regulation working as designed, built on the premise that the surveillance audit programme and the manufacturer's own quality management system carry the rest of the assurance burden.
A sampling plan tells you how much of your portfolio a notified body is checking. It says nothing about the files it didn't pick — those are still live, still certified, and still entirely on your quality system to defend. Why sampling changes the compliance picture, not the obligation
What stays outside the sampling route
The sampling mechanism covers MDR Class IIa and IIb devices (and, under the parallel IVDR provision, Class B and C diagnostics). It does not reach Class III devices or implantable devices: Annex IX requires individual technical documentation assessment for each of those, every cycle, with no representative-sample shortcut. Manufacturers running a mixed portfolio — a Class IIb platform alongside a Class III or implantable line — should not assume uniform notified body scrutiny across the business; the review intensity is genuinely different by classification, and the GSPR compliance matrix work has to be built with that split in mind rather than treated as one undifferentiated technical file programme.
- Map your devices into categories and generic device groups. Confirm how your notified body has grouped your portfolio — the sampling rate applies within each group, not across the whole certificate.
- Treat every file as audit-ready, not just the sampled ones. Build internal technical documentation review into design control and change management, since a device can go a full cycle without notified body eyes on it.
- Confirm which devices sit outside the sampling route. Class III and implantable devices always get individual assessment — plan resourcing accordingly.
- Track the sampling plan across certificate renewal. Ask how sampling rotates across the certificate's validity so an unsampled device this cycle isn't unreviewed indefinitely.
None of this is a loophole to exploit; treating a low sampling probability as license to under-invest in a device's technical file is exactly the posture that turns a routine surveillance audit into a major nonconformity. The practical reading is the opposite: because the notified body's attention is statistically distributed, the manufacturer's own technical documentation review discipline is what is actually catching errors in most of the portfolio, most of the time. That is a design-control and internal audit question before it is ever a notified body question — and it is worth confirming where that ownership sits before your next surveillance cycle decides it for you.
Frequently asked questions
Does a notified body review every device's technical documentation under MDR?
Not under the QMS-based route for Class IIa and IIb devices. Annex VII requires the notified body to maintain a sampling plan, and MDCG 2019-13 sets the baseline rate at 15% of devices per category and generic device group across the certificate's validity, reviewing a representative sample rather than every file.
What sampling rate does MDCG 2019-13 set?
The guidance's baseline is 15% of devices in each category and generic device group covered by the certificate, assessed over the certificate's validity period (up to five years). A 2024 revision allows that rate to be reduced to a minimum of 5% under a transitional footnote.
Which devices are excluded from the sampling approach?
Class III devices and implantable devices are not sampled under this mechanism — Annex IX requires the notified body to assess the technical documentation for each of those devices individually, not on a representative basis.
Sources & further reading
- Medical Device Coordination Group. MDCG 2019-13 Rev.1 — Guidance on sampling of MDR Class IIa/IIb and IVDR Class B/C devices for the assessment of technical documentation. ec.europa.eu
- Regulation (EU) 2017/745 (MDR), Annex VII and Annex IX. eur-lex.europa.eu
This article is provided for general informational purposes and reflects the regulatory landscape as of October 2026. It is not legal or regulatory advice. Confirm current MDR and MDCG sampling requirements with your notified body or qualified counsel before acting.
