Manufacturing & Engineering Product compliance and marking UK-wide

Software and AI as medical devices (SaMD/AIaMD)

How MHRA regulates software and AI-powered medical devices. Covers the SaMD definition and boundary guidance, current classification under UK MDR 2002, future reclassification to Class IIa minimum, Good Machine Learning Practice principles, predetermined change control plans, and clinical evidence for AI.

Guide summary

You must register your software or AI medical device with MHRA before selling it in the UK. From 2026, most devices will need a higher safety class and an approved body check. Follow Good Machine Learning Practice for AI devices, report safety problems to MHRA, and know that selling a non-compliant device can lead to up to 6 months in prison or an unlimited fine.

  • Register SaMD and AIaMD with MHRA before selling in UK
  • From 2026, most devices reclassified to Class IIa or higher
  • Apply Good Machine Learning Practice for AI devices
  • Report serious incidents to MHRA within 2, 10 or 15 days
  • CE marked devices accepted until 30 June 2028 (old rules)
  • EU MDR CE mark accepted until 30 June 2030
  • Placing non-compliant device on market risks 6 months prison or unlimited fine
  • Keep records of algorithm design, training data and limits
  • Use predetermined change control plans for learning algorithms
  • Post-market surveillance starts 16 June 2025 via MORE portal
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Software as a Medical Device (SaMD) is standalone software that qualifies as a medical device in its own right. It is not software that is part of a hardware medical device (which is regulated as part of the hardware device).

SaMD is regulated under the UK Medical Devices Regulations 2002 and must be registered with MHRA before being placed on the GB market. AI as a Medical Device (AIaMD) is a subset of SaMD that uses artificial intelligence or machine learning algorithms.

Is your software a medical device?

Software is a medical device if it has a medical intended purpose, such as:

  • Diagnosis, prevention, monitoring, prediction, prognosis, or treatment of disease
  • Diagnosis, monitoring, treatment, or alleviation of an injury or disability
  • Investigation, replacement, or modification of anatomy or a physiological process

Software that only stores, archives, communicates, or performs simple searches of patient data without processing or analysing it for a medical purpose is not a medical device.

Current classification

Under the current UK MDR 2002, SaMD is classified using the same Annex IX criteria as other general medical devices. Many SaMD products are currently classified as Class I, allowing self-certification without UK Approved Body involvement.

Future reclassification

MHRA will adopt the IMDRF SaMD risk categorisation framework, which considers:

  • The significance of the information provided by the SaMD to the healthcare decision
  • The state of the healthcare situation or condition

Under the new rules, most SaMD will be reclassified as Class IIa at minimum, requiring UK Approved Body involvement. This represents an up-classification for many currently Class I SaMD products. The reclassification is expected via a statutory instrument in 2026.

Good Machine Learning Practice (GMLP)

MHRA expects AIaMD manufacturers to apply GMLP principles:

  • Transparency: Document algorithm design, training data sources, and known limitations
  • Clinical evidence: Demonstrate clinical validity and safety appropriate to the risk classification
  • Predetermined change control plans: For adaptive algorithms that learn over time, establish predetermined change control plans describing what changes the algorithm may make without requiring a new conformity assessment
  • Monitoring: Implement robust post-market surveillance for algorithm performance drift

SaMD and AIaMD guidance