Essential Requirements — overview
The Essential Requirements for general medical devices and AIMDs are in Schedule 1 of the UK MDR 2002. The Essential Requirements for IVD medical devices are in Schedule 1A of the UK MDR 2002 Part III. Conformity with Essential Requirements is a prerequisite for UKCA marking and placing a device on the GB market.
This site provides general information only and does not constitute legal or regulatory advice. Always consult the official legislation and MHRA guidance before preparing Essential Requirements documentation.
What are the Essential Requirements?
The Essential Requirements (ERs) are the fundamental safety and performance standards that every medical device placed on the GB market must satisfy. They are the legal expression of what "safe and effective" means for a medical device under UK MDR 2002.
Essential Requirements are outcome-based — they specify what must be achieved (e.g., "the device must not compromise the clinical condition or safety of patients"), not precisely how to achieve it. Manufacturers have flexibility in the technical means they use to meet each requirement, provided they can demonstrate the required outcome is met.
No device may bear the UKCA mark (or rely on the CE marking transitional acceptance) unless it has been demonstrated to conform with all applicable Essential Requirements.
Where the Essential Requirements are found
| Device type | Essential Requirements location |
|---|---|
| General medical devices (Part I) | Schedule 1, UK MDR 2002 |
| Active implantable medical devices — AIMDs (Part II) | Part II Schedule 1, UK MDR 2002 |
| IVD medical devices (Part III) | Schedule 1A, UK MDR 2002 Part III |
Schedule 1 is structured in two main sections:
- Section I — General requirements applicable to all devices
- Section II — Requirements for devices with specific properties (sterilised devices, devices with a measuring function, devices connected to active devices, radiation-emitting devices, software, etc.)
Schedule 1A (IVDs) follows a similar two-section structure with IVD-specific requirements.
Schedule 1 — Essential Requirements for general devices
Section I: General requirements
ER 1 — No compromise to safety when properly used The device must be designed and manufactured in such a way that when used under the conditions and for the purposes intended, it will not compromise the clinical condition or safety of patients, or the safety and health of users or other persons.
ER 2 — Risk reduction and benefit-risk balance Any risks associated with use of the device must be acceptable when weighed against the benefits to the patient. Risks must be reduced as far as possible without adversely affecting the benefit-risk ratio. Manufacturers must apply a systematic risk management process (ISO 14971).
ER 3 — Performance as intended The device must achieve the performance intended by the manufacturer as stated in the labelling and IFU, and in any promotional materials.
ER 4 — Long-term stability The characteristics and performance of the device must not be adversely affected to the degree that health or safety is compromised during the lifetime of the device, when subjected to the stresses which can occur during normal conditions of use.
ER 5 — Transport and storage The device must be designed and manufactured to maintain its performance during transport and storage (environmental conditions as specified by the manufacturer).
ER 6 — Side effects and undesirable effects must be acceptable Any undesirable side effects must constitute an acceptable risk when weighed against the intended performance.
Section II: Specific requirements
Section II ERs cover specific device types or properties:
| ER | Scope |
|---|---|
| ER 7 | Chemical, physical, and biological properties — biocompatibility, material selection |
| ER 8 | Infection and microbial contamination |
| ER 9 | Devices with a measuring function |
| ER 10 | Devices for connection to external energy sources |
| ER 11 | Devices with a measuring function — additional accuracy requirements |
| ER 12 | Radiation protection requirements |
| ER 13 | Requirements for medical devices connected to or equipped with energy sources |
| ER 14 | Requirements for medical devices incorporating software |
| ER 15 | Active implantable device requirements |
| ER 16–17 | Devices incorporating a substance |
| ER 18 | IFU and labelling requirements |
IFU and labelling requirements (ER 18 in brief)
Every device must be supplied with information needed for safe and effective use. This must include:
- Manufacturer name and address (and UKRP if applicable)
- Intended purpose
- Device description and specification
- Instructions for use (in English for the GB market)
- Warnings, precautions, contraindications
- Sterility status and expiry (if applicable)
- UKCA mark and UKAB identification number (if applicable)
Full labelling requirements are addressed in Labelling requirements.
Schedule 1A — Essential Requirements for IVDs
IVD Essential Requirements are in Schedule 1A of UK MDR 2002 Part III. They address the specific nature of in vitro diagnostic testing:
IVD-specific requirements include:
Analytical performance:
- Analytical sensitivity
- Analytical specificity (including interference from cross-reacting substances)
- Trueness (bias from reference standard)
- Precision (repeatability and reproducibility)
- Limits of detection and quantitation
- Linearity and measuring range
Clinical performance:
- Diagnostic sensitivity and specificity
- Positive and negative predictive values
- Likelihood ratios
- Expected values in normal and affected populations
Design requirements:
- Specimen type and collection requirements
- Calibration traceability to national or international standards
- Stability of reagents and calibrators
- Reference measurement procedures
IFU requirements specific to IVDs:
- Principle of the test
- Intended use and clinical significance
- Performance characteristics
- Interferences and limitations
- Quality control recommendations
- Reference intervals for the target population
Demonstrating conformity with Essential Requirements
Method 1: UK-designated standards
Conformity with a UK-designated standard (the UK equivalent of a harmonised standard) creates a presumption of conformity with the Essential Requirements to which that standard relates. This is the most efficient and defensible route for most requirements.
UK-designated standards include:
- ISO 13485 — Quality Management Systems → supports ERs related to design controls and manufacturing consistency
- ISO 14971 — Risk Management → supports ER 2 (risk-benefit analysis)
- IEC 60601 series — Electrical safety of active medical devices → supports ERs on electrical safety and EMC
- IEC 62304 — Software lifecycle → supports ER 14 (software devices)
- ISO 10993 series — Biological evaluation of medical devices → supports ER 7 (biocompatibility)
- EN ISO 11135 / 11137 / 11138 — Sterilisation processes → supports ER 8
MHRA publishes the current list of UK-designated standards on gov.uk.
Not all EU harmonised standards are also UK-designated standards. Check MHRA's designated standards list — do not assume EU harmonised standard status automatically carries over to UK-designated status.
Method 2: Alternative technical solutions
Where no UK-designated standard exists, or where the manufacturer chooses not to use one, conformity must be demonstrated through other technical means — independent testing, performance data, scientific literature, or other evidence. The manufacturer must explain and justify why the approach taken is equivalent to or superior to applying the relevant standard.
Method 3: Common Specifications (where applicable)
For certain IVD device types, the UK may adopt Common Specifications — technical documents specifying minimum performance requirements that serve as an alternative to standards. This mechanism exists in UK MDR 2002 but has been less used than in the EU context.
The Essential Requirements checklist and traceability matrix
Every manufacturer must maintain an Essential Requirements checklist — a document that:
- Lists every applicable Essential Requirement
- States how the manufacturer demonstrates conformity with each requirement
- References the specific evidence in the technical file that demonstrates conformity (standard applied, test report, clinical data, etc.)
- Identifies any requirements that are not applicable to the device and explains why
This checklist is a core element of the technical file and is reviewed by UKABs during conformity assessment. It must be kept current throughout the device's market life.
A simple structure:
| Essential Requirement | Applicable? | Method of demonstration | Technical file reference |
|---|---|---|---|
| ER 1 — General safety | Yes | Risk management file per ISO 14971; clinical evaluation report | TF Section 5; TF Section 8 |
| ER 2 — Risk-benefit | Yes | Risk management file per ISO 14971 | TF Section 5 |
| ER 7 — Biocompatibility | Yes | ISO 10993-1 biological evaluation; biocompatibility summary | TF Section 6.1 |
| ER 9 — Measuring function | Not applicable — device has no measuring function | N/A | N/A |
Comparison: Essential Requirements vs EU MDR GSPR
Manufacturers coming from an EU MDR background should note that the UK Essential Requirements are less detailed than the EU MDR General Safety and Performance Requirements (GSPR, Annex I):
| Aspect | UK MDR 2002 Schedule 1 | EU MDR 2017/745 Annex I (GSPR) |
|---|---|---|
| Number of requirements | ~18 ERs | 23 chapters with ~100+ specific sub-requirements |
| Level of prescriptiveness | Outcome-based, high-level | Highly detailed, prescriptive |
| Derived from | EU MDD 93/42/EEC (1993) | New generation post-2017 |
| Clinical evidence requirements | Referenced in ERs | Extensively elaborated in Annex I and Art. 61 |
| Software requirements | ER 14 (brief) | Detailed software lifecycle requirements |
The UK ERs are substantively less prescriptive than the EU GSPRs. Manufacturers preparing technical files to EU MDR GSPR standard will typically exceed UK ER requirements — this is not a problem. Manufacturers preparing for UK MDR only should be aware that an EU GSPR-standard technical file is not required for the GB market.
MHRA's reform programme intends to modernise the Essential Requirements framework — likely toward greater alignment with EU MDR GSPR structure. Monitor What's New for updates.
Related pages
- General requirements — ER 1–6
- Design and construction — ER 7–17
- IFU and labelling — ER 18
- IVD Essential Requirements (Schedule 1A)
- Conformity assessment overview
- Technical documentation overview
- UK-designated standards
Official references
| Reference | Description |
|---|---|
| UK MDR 2002, Schedule 1 | Essential Requirements for general devices and AIMDs |
| UK MDR 2002, Schedule 1A (Part III) | Essential Requirements for IVDs |
| MHRA: Guidance on the UK MDR 2002 | MHRA's overarching regulatory guidance |
| MHRA: Designated standards for medical devices | Current list of UK-designated standards |
| ISO 14971:2019 | Risk management — key tool for ER 2 compliance |
| ISO 13485:2016 | QMS standard supporting multiple ERs |
| EU MDR 2017/745, Annex I | EU GSPR — for reference (not binding in GB) |