SaMD Classification Rules: UK MDR, EU MDR, and How to Apply Them to DMHT

Modules 1 and 2 established whether the product is SaMD at all. This module determines its risk class.

Read this note before applying any rule below: the MHRA DMHT guidance (v1.3, last updated July 2026) is explicit that the legal text for classification of SaMD in the new UK framework is still being developed; the current UK framework for Great Britain therefore applies the EU MDD classification rules as carried forward into UK MDR 2002. This is the stated current position, not a gap in the guidance.

CE marking is currently accepted on the GB market: a device certified under the EU MDR can be placed on the GB market until 30 June 2030, and the separate 30 June 2028 deadline applies only to legacy MDD certificates. That makes EU MDR Rule 11 practically relevant for any GB product pursuing CE certification, and the EU MDR route is open to products starting now, not only to devices already certified.

The new UK framework now exists in draft. The Medical Devices (Amendment) Regulations 2026, published in May 2026, are expected to be laid before Parliament in late 2026 and to come into force about six months after they are made, with their international reliance pathway following about a year later.

Three points in the draft matter for this module. It keeps the active-device structure of Rules 9, 10 and 12 and creates no standalone software rule, so the GB analysis below survives the change.

It adds a new Class IIb limb to Rule 10 for devices intended for diagnosis in clinical situations where the patient is in immediate danger, which could raise the class of crisis-triage and suicide-risk tools once in force. And its reliance pathway, drawing on approvals in Australia, Canada and the United States, admits software only through its most demanding route.

One further practical point from the guidance: the main app stores offer a UK category that does not separate Great Britain from Northern Ireland, so a device distributed through them must comply with both GB and NI regimes, which in practice means running both classification analyses below. Practitioners must verify the current MHRA position before relying on any classification analysis in this module.

The content below reflects the MHRA guidance as last updated in July 2026, with later developments noted where they arise.

The single largest source of confusion in DMHT classification is that two different rulebooks ask two different questions about the same product. Rule 10 asks what the function is: does it allow direct diagnosis?

Rule 11 asks what the worst incorrect output could do: how severe is the foreseeable harm? Which question you answer depends only on where the product is placed, and a GB product relying on CE acceptance answers the EU question in practice.

The MHRA DMHT guidance identifies three rules from UK MDR 2002 (which carries forward the EU MDD classification rules) as most applicable to DMHT: Rule 9, Rule 10 and Rule 12. Rule 9 covers active therapeutic devices intended to administer or exchange energy.

For DMHT this is a narrow category: it applies to software that drives or controls a device delivering physical energy to the body, such as a transcranial direct current stimulation app. Most conversational AI, CBT and mood-monitoring products do not engage Rule 9.

Rule 10 covers active devices intended for diagnosis. It produces Class IIa where the device allows direct diagnosis or monitoring of vital physiological processes, and escalates to Class IIb only where incorrect information could cause immediate danger through variations in vital physiological parameters specifically named in the rule: cardiac performance, respiration, and CNS activity.

That escalation trigger is narrow and most DMHT products do not meet it under the UK framework. The Class IIa net, by contrast, is wide: under the MHRA's reading of direct diagnosis below, a large share of DMHT products reach Class IIa.

Rule 12 is the residual rule: all other active devices are Class I. This is where products that do not allow direct diagnosis and do not engage Rule 9 sit.

The MHRA guidance defines direct diagnosis precisely. A device allows direct diagnosis when it provides the diagnosis of the disease or condition by itself, provides decisive information for making a diagnosis, or claims to perform as or support the function of a clinician in performing diagnostic tasks.

For lay users, provision of an indicative diagnosis may be enough. Rule 10 as written speaks of vital physiological processes and never mentions mental health; the bridge to DMHT is the MHRA's own interpretation, set out in section 8.1 of the guidance and applied throughout this module.

On DMHT, the guidance states: “DMHTs that provide the probability of mental health conditions or probability of symptoms highly correlated to mental health conditions, where there is a reliance on this to determine clinical management options, may be considered as providing decisive information. As such, they would be considered as providing a ‘direct diagnosis’ as per rule 10 of the EU MDD and should be regulated as a class IIa medical device.”

UK MDR 2002 contains no classification rules of its own: it gives legal force in Great Britain to the MDD's Annex IX rules, which is why the MHRA cites rule 10 of the EU MDD as the GB rule. Note the breadth: symptoms highly correlated to conditions count, not only named conditions.

A mood score, a sleep pattern, or a worry index relied on for clinical management triggers the rule just as a named diagnosis would. Risk assessment counts too, and may be the clearest case: the guidance's own mapping of clinical tasks places risk assessment, triage, and screening within the diagnosis term, so a crisis-risk score or a suicide-risk flag relied on to decide escalation is decisive information for clinical management, however far from a clinical diagnosis it feels.

This is the analytical sequence a practitioner uses to classify a DMHT product under UK MDR Rule 10. Apply it function by function; the highest classification reached across all functions determines the overall product class.

Rule 11 is the EU MDR classification rule applicable to CE marking for the EU market and Northern Ireland, and to any GB product relying on CE acceptance. It uses a severity-based three-step test that is structurally different from the UK MDR Rule 10 direct-diagnosis analysis.

Under Rule 11 the most contested classification call for DMHT products is whether an incorrect output could cause serious deterioration (IIb) or only significant deterioration (IIa). The EU MDR text does not define these terms with clinical precision and no notified body has published condition-specific guidance for mental health.

The framework below represents F&G Strategy's interpretation based on current EU MDR text, established clinical definitions, and the reasoning a notified body would be expected to apply. It is not formal MHRA, EU Commission or notified body guidance.

Notified body decisions are product-specific and may differ.

For most DMHT products, EU MDR Rule 11 produces an equal or higher classification than UK MDR, never lower. The table below illustrates the divergence for representative product types.

The MHRA's Software and AI as a Medical Device Change Programme is developing a new UK-specific classification framework for SaMD, including DMHT. The rules summarised in this module may change; verify against current MHRA publications before relying on them for client work.