Borderline and classification under the MDR and IVDR have just become more demanding – and more concrete – areas of scrutiny for manufacturers. With the April 2026 revision of the Manual on borderline and classification (Version 5) and the parallel revision of MDCG 2021‑24 on classification, regulators have tightened the interpretive framework around “borderline” and risk class – and they now back it up with an expanding body of published case decisions.

What has changed?

The updated Borderline and Classification Manual now systematically records agreements reached in the Borderline and Classification Working Group (BCWG) under the Helsinki Procedure, covering not only classical borders (devices vs medicinal products, biocides, cosmetics, PPE, food, consumer products) but also complex substance‑based products and software. New and expanded case examples include, among others, nasal sprays with antibodies for COVID‑19, dental biofilm removal products, root‑canal irrigating solutions with NaOCl/CHX, dual‑action creams with menthol and capsaicin, and various apps and calculators. These cases show a clear trend: authorities look beyond claims and marketing language and assess the actual mode of action and state‑of‑the‑art clinical use when deciding qualification and class.

In parallel, MDCG 2021‑24 Rev.1 refines the terminology and structure of the EU classification guidance. Key edits include updated definitions for invasiveness and implantable devices (e.g. replacing “surgical” with “clinical” intervention), clarification of how to apply the rules when several may apply, and revised/expanded rule‑specific tables and “practical issues” notes (notably for Rules 8, 9, 10, 12, 16, 21 and 22). This revision also aligns more explicitly with MDCG guidance on software (MDCG 2019‑11) and on borderline medicinal‑product combinations.

Practical implications for borderline products

For manufacturers of borderline products, several lines of practice are now clearly emerging:

  • Mode of action must be evidence‑based. Products whose principal effect is pharmacological, immunological or metabolic (e.g. menthol/capsaicin creams for pain relief, lactose vaginal tablets modulating flora) are explicitly excluded from the device definition, regardless of how conservatively manufacturers frame their intended use.
  • Ancillary medicinal substances push devices into class III. Where a product is a medical device but incorporates, as an integral part, an ancillary medicinal substance (e.g. root canal irrigating solutions with NaOCl or CHX, adenine in red‑blood‑cell additive solutions), the Manual and MDCG 2021‑24 confirm systematic application of Rule 14 -> class III.
  • “No claim” is not a strategy. Several new cases underline that simply omitting words like “disinfection” or “antimicrobial” does not change the scientific reality of the action; regulators expect robust data showing the absence of pharmacological or metabolic effect if manufacturers rely on a purely mechanical mode of action argument.

From a regulatory‑strategy perspective, this means borderline dossiers will increasingly be judged on mechanistic rationales and supporting data, not on carefully engineered labelling alone.

Classification – more consistency, less flexibility

The revised MDCG 2021‑24 guidance reinforces the risk‑based logic of Annex VIII and reduces room for “creative” class downgrading. For example, new or expanded explanations and examples clarify:

  • Rule 8 and implants/long‑term surgically invasive devices: devices that are implantable and either have a biological effect or are wholly/mainly absorbed (e.g. certain cyanoacrylate‑based vascular adhesives) should be class III; time to absorption cannot be used as an argument for class IIb.
  • Rule 21 substance‑based devices: saline solutions for nasal irrigation – long debated by industry – are now clearly positioned as class IIa devices under Rule 21, not class I under Rule 5, reflecting both local dispersion and the potential for partial ingestion/inhalation.
  • Software under Rule 11: diagnostic/therapeutic decision‑support software and monitoring tools are consistently pushed to class IIa or higher, depending on the criticality of the information and the clinical context.

Manufacturers are expected to document not only the chosen rule, but also why stricter rules do not apply, using MDCG 2021‑24 as an explicit reference point in technical documentation and Notified Body dialogue.

What manufacturers should do now

Given these developments, manufacturers with products anywhere near a borderline or class “edge” should:

  • Re‑screen portfolios against the updated Manual and MDCG 2021‑24, focusing on substance‑based products, combined products, and software.
  • Revisit qualification and classification rationales in technical documentation, ensuring that mode of action, duration of use, invasiveness and clinical context are justified with scientific evidence rather than marketing claims.
  • Expect more scrutiny from Notified Bodies, who will increasingly rely on the BCWG Manual cases and MDCG 2021‑24 when challenging borderline or low‑class positions.

For manufacturers, these changes do not fundamentally rewrite MDR/IVDR, but they significantly raise the bar on consistency and evidence for borderline and classification decisions.