IVDR Class C: The May Deadline Passed. The One That Matters Is in September.

Every IVDR transition deadline gets discussed as though there is one date. For legacy Class C diagnostics there are three, and the industry's attention has been fixed on the one that already passed. Twenty-six May 2026 was the deadline to lodge a formal application with a Notified Body. It was never the deadline that decides whether a device stays on the market. That one falls on 26 September 2026, and a filed application does not, by itself, get a manufacturer there.

Three dates, one condition each

Regulation (EU) 2024/1860 restructured the IVDR transition for legacy devices as a chain of conditions, not a single extension. For a self-declared legacy Class C device to reach 31 December 2028 under Article 110(3c), a manufacturer has to clear each gate on schedule: an IVDR-compliant quality management system under Article 10(8) in place by 26 May 2025; a formal conformity-assessment application lodged with an EU Notified Body by 26 May 2026; and a signed written agreement with that Notified Body by 26 September 2026. Miss any one of the three, and the extension does not apply — the manufacturer is back on IVDR's standard timeline, with none of the transitional runway the amendment was written to provide.

Why an application is not an agreement

The May deadline drew the most coverage because it was concrete and near-term: file by a date, or don't. The September deadline is harder to plan around because it depends on someone else's calendar. A Notified Body does not sign a written agreement the moment an application lands. It signs one once it has enough confidence in a manufacturer's technical documentation to commit its own review capacity — capacity that Notified Bodies across the EU have flagged as constrained well before this transition wave. An application that was filed on time but arrived thin, or that has not been substantively engaged with since filing, is not positioned to convert into a signed agreement before the window closes. Manufacturers who treated 26 May as the finish line and shelved the file are the ones most exposed now.

• Filing and acceptance are not the same event. A Notified Body acknowledging receipt of an application is not the written agreement Article 110(3c)(f) requires.
• Readiness drives scheduling. Notified Bodies are allocating review capacity to applicants whose files are substantially complete first — a common-sense response to a fixed deadline and finite staff.
• Silence since May is a signal. An application with no follow-up correspondence from the Notified Body deserves an active status check now, not in August.
• The clock does not pause for a Notified Body's backlog. A manufacturer's application being queued behind others does not extend 26 September.

A submitted application is a request. A written agreement is a commitment. Regulation (EU) 2024/1860 only rewards the second one. Why 26 September, not 26 May, is the deadline that decides market access

What losing the extension actually means

A device that fails to secure a signed agreement by 26 September 2026 does not get a second extended runway to try again. It falls outside Article 110(3c), which means the transitional placement the amendment created no longer applies to it. In practice that leaves a manufacturer choosing between completing full IVDR conformity assessment on a compressed timeline with no transitional cushion, or addressing the device's EU market status directly with its Notified Body and national competent authority. Neither is a decision a regulatory or quality leader wants to be making for the first time in October.

The obligations that continue regardless of transition status are worth restating, because they get lost in deadline-focused planning: post-market surveillance, vigilance reporting, and EUDAMED registration obligations apply to legacy devices throughout the transitional period, not just once full certification is achieved. A device that is technically still eligible under Article 110(3c) but has let its PMS or vigilance discipline slip is carrying a second, quieter risk alongside the September deadline.

Securing the agreement is the start of the work, not the end

Manufacturers who land a signed agreement by 26 September understandably treat it as the milestone. It is better read as the moment the real assessment begins. The written agreement commits the Notified Body to conduct a full IVDR conformity assessment against a technical file that, until now, may only have needed to be complete enough to justify a filing date. Between the signed agreement and the 31 December 2028 deadline, that file has to hold up to substantive review — performance evaluation, analytical and clinical evidence, risk management documentation, and a quality system the Notified Body can audit, not just attest to on paper.

Two years sounds like generous runway until it is mapped against a realistic Notified Body review cycle, which routinely runs 12 to 18 months for a Class C IVD once substantive review starts, with rounds of questions and responses in between. A manufacturer that spends the next several quarters treating the signed agreement as a pause before deadline pressure returns will find the 2028 date arriving with far less slack than 26 September appeared to buy. The manufacturers who come out ahead are the ones who use the newly secured review slot as the trigger to finalize the technical file immediately, not the signal that the pressure is off.