Classify your medical device for the GB market

Before you can place a medical device on the Great Britain market, you must determine its risk classification. The classification determines which conformity assessment route applies and whether you need a UK Approved Body to certify your device.

Classification rules are in Annex IX of the retained EU Medical Devices Directive (93/42/EEC), applied through the Medical Devices Regulations 2002. Classification depends on the device's intended purpose, invasiveness, duration of body contact, and whether it is active.

Medical device classification system

Risk-based classification system for medical devices determining regulatory pathway.

Class I (lowest risk): Non-invasive devices with minimal risk — self-certification by manufacturer (e.g., bandages, wheelchairs, stethoscopes)
Class Is (sterile, low risk): Sterile low-risk devices — self-certification plus UK Approved Body assessment for sterility aspects (e.g., sterile bandages, sterile surgical gloves)
Class Im (measuring, low risk): Low-risk devices with measuring function — self-certification plus UK Approved Body for metrological aspects (e.g., non-invasive thermometers, graduated syringes)
Class IIa (low-medium risk): Short-term invasive devices and diagnostic equipment — UK Approved Body assessment required (e.g., hearing aids, dental crowns, blood pressure monitors)
Class IIb (medium-high risk): Long-term invasive and surgically invasive devices — UK Approved Body full assessment required (e.g., ventilators, blood bags, condoms)
Class III (highest risk): Devices contacting heart or CNS, containing medicinal substances, or made from animal tissue — UK Approved Body full design examination and QMS assessment (e.g., heart valves, hip implants, coronary stents, pacemakers)
Active implantable medical devices (AIMD): Devices totally or partially introduced into the human body and intended to remain — UK Approved Body full assessment required (e.g., cardiac pacemakers, cochlear implants, neurostimulators)
Classification basis: Classification determined by intended purpose, invasiveness, duration of body contact, and whether device is active — rules in Annex IX of retained Directive 93/42/EEC

Medical device classification guidance

Classification by conformity assessment route

Your device class determines how much regulatory scrutiny it receives:

Class I (non-sterile, non-measuring): Self-certification. You draw up the Declaration of Conformity yourself. No UK Approved Body needed.
Class Is (sterile) and Im (measuring): Self-certification for the device itself, but a UK Approved Body must assess the sterility or metrological aspects.
Class IIa: UK Approved Body assessment required. Options include product verification, quality system audit, or type-examination.
Class IIb: UK Approved Body full assessment required. Type-examination or full quality assurance system audit.
Class III: Most rigorous route. UK Approved Body must conduct full design examination and quality system assessment, including clinical data review.

Active implantable medical devices

Active implantable medical devices (AIMDs) are regulated under Part III of the UK MDR 2002. These are devices intended to be totally or partially introduced into the human body and remain after the procedure. Examples include cardiac pacemakers, implantable defibrillators, cochlear implants, and neurostimulators.

All AIMDs require UK Approved Body full assessment. Only BSI Assurance UK Ltd is currently designated for Part III (active implantable devices).

In vitro diagnostic devices (IVDs)

IVDs are regulated under Part IV of the UK MDR 2002. Under the current system, IVDs are classified by annexes rather than risk-based classes:

Annex II List A: High-risk IVDs such as blood grouping and HIV testing reagents. Require UK Approved Body assessment.
Annex II List B: Moderate-risk IVDs such as pregnancy and fertility tests. Require UK Approved Body assessment.
Self-testing devices: Devices intended for lay persons. Require UK Approved Body assessment for suitability for self-testing.
General IVDs: All other IVDs. Self-certification by manufacturer.

Future IVD classification: MHRA will introduce a new risk-based system with four classes (A to D), aligning with international standards. Class A (lowest risk) will allow self-declaration. Class B will require QMS certification. Classes C and D will require UK Approved Body assessment. This change is expected via a statutory instrument in 2026.

MHRA AI medical device requirements

Requirements for AI as a Medical Device (AIaMD) and Software as a Medical Device (SaMD) under UK medical device regulations.

AI as a Medical Device (AIaMD) and Software as a Medical Device (SaMD) must be registered with MHRA before being placed on the UK market. The MHRA has a dedicated Software Group developing regulatory requirements for AI-powered medical devices. Manufacturers must apply Good Machine Learning Practice (GMLP) principles.

Registration required: All AIaMD and SaMD must be registered with MHRA before being placed on the UK market
Current classification: SaMD classified under Medical Devices Regulations 2002 Annex IX — currently can be Class I to III depending on intended purpose and risk
Future reclassification (expected 2026): MHRA will adopt IMDRF SaMD risk framework — most SaMD will be reclassified to Class IIa minimum, requiring UK Approved Body involvement (up-classification for many currently Class I products)
International reliance: Streamlined approval for devices already authorised by FDA (US), Health Canada, TGA (Australia), or EU Notified Bodies — excludes SaMD
CE mark transition: CE marked SaMDs recognised in UK until 30 June 2028 (old Directives) or 30 June 2030 (EU MDR certified)
Good Machine Learning Practice (GMLP): MHRA expects AIaMD manufacturers to apply GMLP principles — transparency in algorithm design, appropriate clinical evidence, predetermined change control plans for adaptive algorithms
Post-market surveillance: Enhanced PMS requirements from 16 June 2025 — manufacturers must monitor via MORE portal, report incidents within 2/10/15 day statutory timelines
Criminal offence: Placing a non-compliant AI medical device on the UK market — up to 6 months imprisonment and/or unlimited fine

Getting classification advice

If you are unsure how to classify your device, MHRA offers a Devices Regulatory Advice Meeting service. You can request a one-hour meeting to discuss classification, conformity assessment, or regulatory strategy. This is a fee-based service.

For borderline cases, MHRA may issue a formal classification decision on request.

UK Approved Bodies for medical devices

Designated UK Approved Bodies authorised to conduct conformity assessments for medical devices under UK MDR 2002.

Total UK Approved Bodies designated: 7
BSI Assurance UK Ltd (0086): Parts II, III, and IV (general medical devices, active implantable devices, IVDs) — broadest scope
SGS United Kingdom Ltd (0120): Part II (general medical devices)
UL International (UK) Ltd (0843): Parts II and IV (general medical devices, IVDs)
DEKRA Certification UK Ltd: Part II (general medical devices)
TUV SUD BABT: Part II (general medical devices)
Intertek: Part II (general medical devices)
TUV Rheinland UK Ltd: Parts II and IV (general medical devices, IVDs)
Part II scope: General medical devices (MDD)
Part III scope: Active implantable medical devices (AIMDD)
Part IV scope: In vitro diagnostic medical devices (IVDD)
How to select an Approved Body: Based on device class, intended use, and the body's scope of designation

UK Approved Bodies for medical devices

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Classify your medical device for the GB market

Classification by conformity assessment route

Active implantable medical devices

In vitro diagnostic devices (IVDs)

Getting classification advice

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Classification by conformity assessment route

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In vitro diagnostic devices (IVDs)

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