The FDA has been harmonising its Quality System Regulation — 21 CFR Part 820, historically known as the QSR — with ISO 13485 through an initiative commonly referred to as the Quality Management System Regulation, or QMSR. For EU startups, this means the US QMS framework is moving structurally closer to the ISO 13485 baseline that already anchors MDR Article 10(9) via EN ISO 13485:2016+A11:2021. The transition does not erase the FDA's own expectations, it does not replace any premarket submission, and it does not turn an ISO 13485 certificate into an FDA pass. What it does is reduce the structural gap between the two systems for manufacturers who build their QMS honestly from day one. This post is the EU-founder orientation. Current transition timelines, implementation dates, and inspection parameters should be verified with a US regulatory specialist before any specific plan is committed.

By Tibor Zechmeister and Felix Lenhard. Last updated 10 April 2026.

TL;DR

  • The FDA's Quality System Regulation is codified at 21 CFR Part 820, historically referred to as the QSR. The FDA has been moving this framework toward harmonisation with ISO 13485 under the Quality Management System Regulation (QMSR) initiative.
  • The QMSR does not replace ISO 13485 with something new. It brings Part 820 closer to ISO 13485 while preserving FDA-specific requirements that EU manufacturers cannot ignore.
  • For EU startups whose QMS is already built against EN ISO 13485:2016+A11:2021 to support MDR Article 10(9), the QMSR transition narrows the structural gap between the EU and US QMS baselines. It does not eliminate the gap.
  • The transition is a QMS framework change, not a market-access change. A 510(k), De Novo, or PMA is still a separate submission. An ISO 13485 certificate is still not an FDA clearance.
  • Specific implementation dates, inspection model details, and current FDA guidance on the QMSR should be verified directly with a US regulatory specialist — the trajectory is clear, the details evolve.

Why this transition matters for EU founders

A Vienna-based founder Tibor worked with had built a careful ISO 13485 QMS for her MDR project. The quality manual was lean, the procedures described real operations, and the document control was honest rather than decorative. She had read that the FDA was harmonising 21 CFR Part 820 with ISO 13485 and assumed that her ISO 13485 certificate would, once the transition took effect, be enough for US market access on the QMS side. She told an investor so. The investor, who had sat through FDA inspections in a previous life, raised an eyebrow and asked her to verify the claim.

She verified. The harmonisation was real. The assumption that ISO 13485 alone equals an FDA pass was not. The QMSR brings Part 820 structurally closer to ISO 13485, but it does not delete the FDA's specific requirements, its own inspection expectations, or its record-keeping norms. The founder's QMS was a strong starting point. It still needed a gap analysis against the US-specific overlay. She did the gap work early, closed the gaps before they became audit findings, and kept the investor relationship intact.

This is the pattern worth internalising. The QSR-to-QMSR transition is a genuine simplification of the transatlantic QMS landscape for manufacturers who understand what it actually changes. It is a trap for manufacturers who read a headline and conclude that ISO 13485 now equals FDA compliance. This post is the honest orientation for the first group.

A note on the boundary of our expertise, stated once and clearly: Tibor's authority is the EU MDR and the Notified Body system. FDA-specific framing in this post stays at the general level on purpose. Specific CFR provisions, current QMSR implementation dates, inspection model parameters, and Part 820 gap analysis at the implementation level belong to a US regulatory specialist who practices inside the FDA system daily.

What the QSR was — and still is, at the time of writing

The FDA's Quality System Regulation has for decades been codified at 21 CFR Part 820, the part of the US Code of Federal Regulations that sets out the current good manufacturing practice requirements for medical device manufacturers selling into the United States. It has historically been referred to as the QSR. It covers the standard QMS process areas — management responsibility, design controls, document controls, purchasing controls, production and process controls, corrective and preventive action, handling, storage, distribution, installation, servicing, records, statistical techniques — in language and structure that was written before ISO 13485 reached its current form and that diverged from ISO 13485 on several implementation details.

The consequence for EU founders has been structural duplication. A manufacturer selling into both the EU and the US has historically maintained a QMS that satisfies ISO 13485 (for CE marking via MDR Article 10(9), with EN ISO 13485:2016+A11:2021 as the harmonised standard) and also satisfies the distinct terminology, structure, and specific requirements of 21 CFR Part 820. The underlying processes overlapped heavily, but the documentation, the terminology, and the audit preparation often ran on two parallel tracks. Startups with limited regulatory bandwidth paid for this duplication in time, rework, and late-discovered gaps.

The QSR, as it has existed, is not wrong or obsolete. It is the framework the FDA has used to regulate device QMS in the US for decades, and it has inspected manufacturers against it for most of that period. The transition to the QMSR does not discard that history. It moves the framework forward.

The QMSR transition concept at the general level

The Quality Management System Regulation — QMSR — is the FDA's initiative to bring 21 CFR Part 820 into closer alignment with ISO 13485. At the general level, the move incorporates ISO 13485 more directly into the regulatory text, reduces structural divergence between the two frameworks, and preserves the FDA's specific legal and enforcement expectations alongside the incorporated ISO content.

We are keeping the framing at the general level deliberately. Specific citations inside 21 CFR Part 820 beyond that high-level identifier, the exact implementation date, the transition window for existing inspections, and the mapping between Part 820 subparts and ISO 13485 clauses are the domain of current FDA guidance and a US regulatory specialist's practice. The trajectory — harmonisation with ISO 13485, preservation of FDA-specific obligations, change in the operating model for QMS inspections — is well established. The details are not static, and a post written for EU founders should not pretend otherwise. Anything material to your specific plan should be verified with a US specialist at the time you commit to action, not copied from a blog post.

What is safe to say at the general level: the QMSR reduces structural gap, it does not eliminate FDA-specific obligations, and it does not change the legal framework for premarket submissions. An EU startup reading this post should walk away with the orientation, not with a compliance checklist.

How ISO 13485 becomes the reference

The practical shape of the harmonisation is that ISO 13485 — specifically the version incorporated by the FDA in its regulatory text — becomes the structural reference for the US QMS framework. A manufacturer operating a real ISO 13485 QMS is, under the QMSR, operating a QMS that aligns with most of the structural expectations the FDA will apply.

Most is not all. The FDA retains specific requirements that go beyond ISO 13485 on topics where US law sets its own bar. These include but are not limited to the US-specific obligations around complaint handling, records retention, labelling, device tracking where applicable, and the FDA's own inspection authority and enforcement tools. A QMS that is "ISO 13485 only" and has not been extended to meet the FDA-specific overlay is not a QMS that the FDA will accept without findings.

For EU startups, the mental model is similar to the one that already applies for MDSAP. ISO 13485 is the spine. Country-specific overlays are the layers that extend the spine to cover each regulator's specific expectations. Under the QMSR, the US overlay is smaller than it was under the pre-harmonisation QSR, but it is not zero. The spine-plus-overlay architecture is the right way to think about a multi-market QMS in 2026, and the QSR-to-QMSR transition makes that architecture cleaner rather than changing it.

What EU startups with ISO 13485 gain

If your startup already runs a real ISO 13485 QMS built to support MDR Article 10(9) — with EN ISO 13485:2016+A11:2021 as the harmonised reference — the QMSR transition gives you three concrete advantages over the pre-harmonisation state.

The first advantage is structural reuse. The process areas, the terminology, the document structure, and the records architecture of your ISO 13485 QMS map more directly onto the FDA's framework than they did before. This reduces the translation work when you prepare for FDA inspection. It does not reduce it to zero.

The second advantage is conceptual coherence. Your team can build, train, and operate a single QMS around a single structural reference instead of maintaining two mental models for the EU and the US. For a small team with limited regulatory bandwidth, this matters more than the words on a certificate. A QMS that the whole team understands is worth more than a QMS that exists in parallel versions no one can hold in their head.

The third advantage is audit efficiency. Combined audits — where the same Auditing Organisation performs an MDR Notified Body audit and an MDSAP audit covering the FDA in coordinated visits — become cleaner when the underlying frameworks are closer together. The audits remain separate assessments against separate frameworks, but the calendar time, the document preparation, and the follow-up work scale down compared to a world where the two frameworks had less in common.

None of this translates into "ISO 13485 is enough for the FDA." It translates into "ISO 13485 is a closer starting point, and the remaining work is smaller and more targeted." That is a real gain. It is not a free pass.

What EU startups still need to do differently for FDA

The QMSR reduces the gap. It does not delete the US-specific layer. EU startups selling into the US still need to plan for several things that an MDR-only QMS does not cover by default.

A US Agent. Foreign manufacturers selling devices into the US must designate a US Agent as the FDA's point of contact. This is an administrative requirement, not a strategic choice, and it is unchanged by the QMSR.

Establishment registration and device listing. Manufacturers selling into the US must register their establishment with the FDA and list their devices, on the FDA's schedule and in the FDA's format. This is a separate activity from the MDR registration obligations and the Eudamed entries required by the EU framework.

Premarket submissions. A 510(k), De Novo, or PMA is a separate regulatory activity with its own evidence base and review process. The QMSR does not change what a premarket submission contains. A harmonised QMS framework does not remove the need to submit the device itself for FDA clearance or approval through the appropriate pathway.

FDA-specific records and complaint handling expectations. Even under the QMSR, the FDA has specific views on what complaint files look like, how records are retained and made available to inspectors, and how corrective actions are documented. A gap analysis against these specifics remains part of any serious US-entry plan.

Inspection readiness. The FDA inspects manufacturers. The mechanics of an FDA inspection — whether performed by FDA investigators directly or by an MDSAP Auditing Organisation operating under the program — differ from an EU Notified Body audit in tone, pace, and documentation expectations. Preparing a team for an FDA-style inspection is a specific piece of work that cannot be outsourced to a generic ISO 13485 training.

Each of these items survives the QMSR transition. Each of them belongs on the dual-market plan from day one.

Timeline framing

We are intentionally not quoting a specific QMSR implementation date in this post, because the details have moved during the transition and EU founders reading a blog post months after publication deserve current information rather than stale specifics. The honest framing is this: the FDA announced the QMSR harmonisation initiative, set out a transition period during which existing Part 820 expectations phase into the new harmonised framework, and published guidance that continues to evolve.

For any specific planning decision — when your QMS gap analysis against QMSR expectations should be completed, when a combined MDR plus MDSAP audit should be scheduled, when your FDA inspection readiness should peak — confirm the current implementation status with a US regulatory specialist or directly against current FDA guidance. Do not commit to a specific date based on anything you read in a blog post, including this one. The trajectory is stable. The specific dates are the kind of fact that deserves a live check.

A pragmatic rule for startups: if the US is in your business plan within the next 24 months, treat the QMSR framework as your working US QMS reference today. If the US is further out, keep a watching brief on the specific transition parameters and revisit the plan when the market becomes real.

Common misunderstandings worth correcting

"The QMSR means ISO 13485 is now enough for the FDA." No. The QMSR harmonises Part 820 with ISO 13485 while preserving FDA-specific obligations. An ISO 13485 certificate is not, by itself, evidence of FDA compliance.

"The QMSR replaces premarket submissions." No. The QMSR addresses the QMS framework. Premarket submissions — 510(k), De Novo, PMA — are a separate legal layer and are unchanged by the harmonisation.

"The QMSR means EU manufacturers do not need a US Agent anymore." No. Foreign manufacturer obligations around US Agent designation, establishment registration, and device listing are unchanged by the QMSR. They exist outside the QMS framework.

"MDSAP is obsolete now that the QMSR exists." No. MDSAP remains the multi-market QMS audit programme and continues to be effectively mandatory for Health Canada. The QMSR changes the FDA-side framework; it does not replace the multi-jurisdictional audit mechanism.

"The transition is over and everyone is on the new framework." It depends on when you read this. Confirm with a US specialist rather than assuming.

The Subtract to Ship angle

The Subtract to Ship framework — strip every activity that does not trace back to a specific regulatory obligation — applies cleanly to the QMSR transition. The subtraction targets are the duplications the old QSR forced: parallel "US QMS" binders, separate US-only procedures that now have no distinct home under a harmonised framework, documentation formats designed to translate between two divergent structures. These come out.

What survives subtraction is the spine-plus-overlay architecture. One real QMS built on ISO 13485 (EN ISO 13485:2016+A11:2021 for MDR Article 10(9)), with a US-specific overlay that covers the FDA obligations not already absorbed by the harmonised framework. The overlay is smaller than it used to be. The obligation to have an overlay is still there.

The pattern we see in EU founders who handle the QMSR transition well is not "do less US work." It is "do less duplicative work, and do the remaining US-specific work deliberately and early." False economies — skipping the gap analysis, assuming ISO 13485 alone is enough, treating the transition as a deletion rather than a harmonisation — are the waste the framework removes. Real FDA-specific work is the waste the framework protects.

See the Subtract to Ship framework for MDR for the foundational methodology this applies, and MDSAP: using a single audit for multiple markets for the audit-level expression of the spine-plus-overlay pattern in a multi-jurisdictional setting.

Reality Check — Where do you stand on the QMSR transition?

  1. Is the United States in your business plan within the next 24 months with a target launch date and a revenue assumption, or is it still a "someday" item?
  2. Do you operate a real ISO 13485 QMS built to support MDR Article 10(9), or a template binder that would not survive any serious audit?
  3. Have you had a US regulatory specialist confirm the current QMSR implementation status and what it means for your specific device and timeline?
  4. Have you done — or scoped — a gap analysis between your current ISO 13485 QMS and the US-specific overlay expectations under the QMSR?
  5. Do you understand that the QMSR does not replace any premarket submission, and that your 510(k), De Novo, or PMA plan is unchanged by the transition?
  6. Have you confirmed whether MDSAP is the right audit mechanism for your multi-market QMS work, given which jurisdictions are actually in your plan?
  7. If an investor asked you today whether an ISO 13485 certificate is enough for FDA compliance under the QMSR, would your answer be accurate?

If you cannot answer more than three of these seven clearly, your US QMS plan is not a plan yet.

Frequently Asked Questions

Does the QMSR mean an ISO 13485 certificate is enough for FDA compliance? No. The QMSR harmonises 21 CFR Part 820 with ISO 13485 structurally, but it preserves FDA-specific obligations that go beyond the ISO 13485 baseline. An ISO 13485 certificate is a strong starting point. It is not, by itself, evidence of FDA compliance. A gap analysis between the ISO 13485 QMS and the US-specific overlay is still required.

Does the QMSR change what a 510(k) submission contains? No. The QMSR addresses the QMS framework. A 510(k), De Novo, or PMA premarket submission is a separate regulatory activity with its own evidence base and its own review process. Those submissions are unchanged by the QMSR at the framework level.

Does the QMSR remove the need for a US Agent or establishment registration? No. Foreign manufacturer obligations around US Agent designation, establishment registration with the FDA, and device listing are outside the QMS framework and are unchanged by the QMSR.

Is MDSAP still relevant after the QMSR? Yes. MDSAP remains the multi-market QMS audit programme covering five participating authorities, and it remains effectively mandatory for Health Canada at Class II and above under the Canadian classification. The QMSR changes the FDA-side QMS framework; it does not replace MDSAP as the mechanism that allows a single audit to satisfy multiple jurisdictions.

When does the QMSR take effect? The FDA has published a transition plan for the QMSR initiative. Specific implementation dates, transition windows, and inspection model parameters have evolved since the announcement, and any plan you commit to should be verified against current FDA guidance or a US regulatory specialist at the time of commitment. We deliberately do not pin a date in this post because EU founders reading it months after publication deserve current information.

What should an EU startup actually do today about the QMSR? If the US is in your 24-month plan, treat the harmonised QMSR framework as your working US QMS reference, build your ISO 13485 QMS honestly around EN ISO 13485:2016+A11:2021, scope a gap analysis against the US-specific overlay, and engage a US regulatory specialist to confirm current implementation parameters before committing to audit timing. If the US is further out, keep a watching brief and revisit when the market becomes real.

Where does Zechmeister Strategic Solutions sit in this? On the EU MDR and Notified Body side. Tibor does not hold himself out as an FDA specialist, and the FDA framing in this post stays deliberately at the general level. For the specific US-side work — Part 820 gap analysis at implementation level, current QMSR implementation dates, FDA inspection preparation, establishment registration, US Agent selection — work with a US regulatory specialist who practices inside the FDA system daily.

Sources

  1. Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices (MDR), in particular Article 10(9) on manufacturer QMS obligations. Official Journal L 117, 5.5.2017.
  2. EN ISO 13485:2016+A11:2021 — Medical devices — Quality management systems — Requirements for regulatory purposes. The harmonised standard providing presumption of conformity with MDR QMS obligations and the structural reference that the FDA's QMSR harmonisation initiative brings 21 CFR Part 820 closer to.
  3. U.S. Code of Federal Regulations, Title 21, Part 820 — historically the Quality System Regulation (QSR), transitioning to the Quality Management System Regulation (QMSR) under the FDA harmonisation initiative. Referenced at the general framework level; for current transition dates, inspection model parameters, and specific Part 820 provisions, consult current FDA guidance or a US regulatory specialist.
  4. U.S. Food and Drug Administration — Center for Devices and Radiological Health (CDRH), public guidance on the QMSR transition. Referenced at the general framing level; verify current status before committing to any specific plan.
  5. Medical Device Single Audit Program (MDSAP) — programme documentation maintained by the International Medical Device Regulators Forum (IMDRF). Referenced for the multi-market QMS audit context in which the QMSR transition lands.

This post is part of the FDA & International Market Access series in the Subtract to Ship: MDR blog. Authored by Felix Lenhard and Tibor Zechmeister. A note on the limits of our expertise, stated once and clearly: Tibor's authority is in the EU MDR and the Notified Body system, and the FDA framing in this post stays deliberately at the general level. For specific US-side work — the current QMSR implementation status, 21 CFR Part 820 gap analysis at implementation level, FDA inspection preparation, establishment registration, and US Agent selection — work with a US regulatory specialist who practices inside the FDA system daily. This post is the orientation. The specialist is the execution.