Contributor: Sana Shaikh
Medical Device Categorisation, Classification and Regulation in the United Kingdom
Having a thorough understanding of the classification and class of your medical device is vital for navigating the appropriate regulatory assessment route and achieving market authorisation. While the scope of medical devices is incredibly broad, for regulatory purposes in the UK, they are classified based on device type, duration of use, and level of risk. All medical devices placed on the UK market must be designated a category and a risk classification to undergo the regulatory approval process.
In Great Britain (England, Scotland, and Wales), medical devices are now regulated by the Medicines and Healthcare products Regulatory Agency (MHRA) under the new core UK medical device regulatory framework, which fully came into effect earlier this year, replacing the legacy UK MDR 2002. Northern Ireland, however, continues to follow the EU Medical Devices Regulation (MDR 2017/745) and In Vitro Diagnostics Regulation (IVDR 2017/746) under the Windsor Framework. In the EU, devices are regulated by national Competent Authorities (e.g., BfArM, ANSM) and Notified Bodies, not the European Medicines Agency (EMA), which oversees medicines.
Category (Type) of Medical Device
The MHRA categorises medical devices into the following five broad types:
- Non-invasive: Devices which do not enter the body.
- Invasive: Devices which, in whole or in part, are inserted into the body’s orifices (including the external eyeball surface) or penetrate the surface of the body, such as the skin.
- Surgically invasive: Devices used or inserted surgically that penetrate the body through the surface of the body.
- Active: Devices requiring an external source of power, including stand-alone software.
- Implantable: Devices intended to be totally or partially introduced into the human body (including to replace an epithelial surface or the surface of the eye) by surgical intervention and to remain in place after the procedure.
Duration of Use Category
Medical devices are further categorised based upon their intended duration of continuous use under normal circumstances:
- Transient: Intended for less than 60 minutes of continuous use.
- Short term: Intended for between 60 minutes and 30 days of continuous use.
- Long term: Intended for more than 30 days of continuous use.
UKCA Mark & Conformity Assessment
For the purposes of conformity assessment and marking, the MHRA designates three overarching categories:
- General medical devices: Most medical devices fall into this category.
- Active implantable devices: Devices powered by implants or partial implants intended to remain in the human body after a procedure.
- In vitro diagnostics medical devices (IVDs): Equipment or systems used in vitro to examine specimens derived from the human body.
To place a device on the market in Great Britain, manufacturers can use either the UKCA (UK Conformity Assessed) mark or the CE mark. The UK government allows an indefinite extension for CE mark recognition alongside the domestic UKCA mark for medical devices. This dual-recognition policy provides flexibility for manufacturers operating in both the UK and EU markets. However, the UKCA mark remains the specific domestic mark for Great Britain. In contrast, Northern Ireland continues to require the CE mark under the EU MDR and IVDR frameworks.easures allowed CE marks to be recognised post-Brexit, manufacturers are now required to transition to UKCA marking to align with the new domestic regulations.
Risk Classification for General Medical Devices and Active Implantable Devices
In the UK and EU, there are four official risk-related classes for general and active implantable medical devices. The class a device falls into is largely informed by its category and intended duration of use.
- Class I: Generally regarded as low risk (e.g., stethoscopes, bandages, surgical masks). This includes subclasses Class Is (sterile), Class Im (measuring function), and Class Ir (reusable surgical instruments). Most Class I devices require only self-assessment and self-certification by the manufacturer, though sterile and measuring variants require Approved Body involvement.
- Class IIa: Low to medium risk (e.g., dental fillings, surgical clamps, tracheotomy tubes). Requires UK Approved Body (Notified Body) assessment.
- Class IIb: Medium to high risk (e.g., lung ventilators, bone fixation plates). Requires UK Approved Body assessment.
- Class III: High potential risk (e.g., pacemakers, drug-coated stents, spinal disc cages). Subject to the strictest regulations, including a design dossier examination by a UK Approved Body.
Risk Classification for In Vitro Diagnostic Medical Devices (IVDs)
Under the new 2026 UK framework, Great Britain has fully transitioned away from the legacy list-based system (Annex II List A/B) and now operates under a harmonised, risk-based classification system mirroring the EU IVDR. IVDs in the UK are now classified as follows:
- Class A: Low risk (e.g., laboratory devices, instruments, specimen receptacles). Requires self-declaration.
- Class B: Low-to-medium risk. Requires UK Approved Body involvement.
- Class C: Medium-to-high risk (e.g., companion diagnostics, genetic screening, some self-testing devices). Requires UK Approved Body design dossier review.
- Class D: Highest risk (e.g., blood donor screening for HIV/Hepatitis, ABO blood grouping). Requires stringent UK Approved Body review and batch verification.
Implemented Up-Classification of Novel Technologies
As part of the 2026 regulatory update, the MHRA has formally up-classified several novel device types to the highest risk category, Class III, to accommodate evolving technologies and enhance patient safety. Devices now regulated as Class III include:
- Active implantable medical devices and their accessories
- In vitro fertilisation (IVF) and Assisted Reproduction Technologies (ART)
- Surgical meshes
- Total or partial joint replacements
- Spinal disc replacements and devices contacting the spinal column
- Medical devices containing nanomaterials or absorbable substances
- Active therapeutic devices with an integrated diagnostic function (e.g., closed-loop systems)
- Certain Software as a Medical Device (SaMD) and AI-driven diagnostics
With this shift to higher risk classifications comes an increased demand for robust clinical evidence and clinical investigations to meet regulatory approval. While this increases the burden for manufacturers, it ultimately ensures greater patient safety and efficacy.
Medical devices are incredibly heterogeneous. Accordingly, medical device research and development requires an interdisciplinary approach. During R&D, it is crucial to understand the intended user, the circumstances of use, and the device’s risk status to successfully navigate the appropriate regulatory approval pathway.
References
Factsheet: medical devices overview – GOV.UK (www.gov.uk)
[1] https://www.gov.uk/government/collections/guidance-on-class-1-medical-devices
[2] https://www.gov.uk/guidance/medical-devices-how-to-comply-with-the-legal-requirements
[3] https://www.gov.uk/guidance/medical-devices-conformity-assessment-and-the-ukca-mark
[4] https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/640404/MDR_IVDR_guidance_Print_13.pdf[5] https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/946260/IVDD_legislation_guidance_-_PDF.pdf
