Manufacturing & Engineering Product compliance and marking UK-wide

Classify your medical device for the GB market

How to classify your medical device under the UK Medical Devices Regulations 2002. Covers Class I through III for general devices, active implantable devices, IVDs (current Annex system and future Class A-D), and Software as a Medical Device.

Guide summary

You must classify your medical device by risk before you place it on the GB market. The class decides how much checking your device needs and whether you need a UK Approved Body. The rules depend on what your device does, how long it touches the body, and if it is active or sterile.

  • Find your device class using Annex IX of the Medical Devices Regulations 2002
  • Class I (lowest risk): you can self-certify – no UK Approved Body needed
  • Class Is (sterile) and Im (measuring): self-certify but get UK Approved Body for sterility or measuring
  • Class IIa, IIb, III and active implants: you must use a UK Approved Body for checks
  • All software as a medical device must register with MHRA before sale
  • Most software will move to Class IIa or above from 2026 – needs UK Approved Body
  • For IVDs: List A and B and self-test kits need UK Approved Body – general ones self-certify
  • New IVD classes A to D start in 2026 – Classes C and D need UK Approved Body
  • Placing a non-compliant AI device on the market is a criminal offence – up to 6 months jail
On this page

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Medical device compliance checklist

Verification checklist for medical device manufacturers and UK Responsible Persons. Covers device classification, conformity assessment, technical documentation, UKCA/CE …

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.

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.

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.

Classification guidance