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Device description & specifications

Regulatory basis

The technical file requirement is implicit in the conformity assessment procedures of Schedule 3, UK MDR 2002, and made explicit in MHRA guidance. The device description and specification is the first and foundational element of the technical file.

Purpose of the device description section​

The device description section establishes what the device is — before any claims about safety or performance. It provides the context in which all other technical file sections (risk management, clinical evaluation, testing) are interpreted. A poorly written device description creates ambiguity throughout the entire technical file.

Required contents​

1. Device name and general description​

  • Trade name (if any) and common/generic name
  • Brief description of the device and its components in plain language
  • Device generation or version (if applicable)
  • Images, diagrams, or photographs showing the device and its key features

2. Intended purpose​

The intended purpose must be precisely stated. It must align exactly with:

  • The labelling and IFU
  • The promotional materials
  • The clinical evaluation scope
  • The risk management scope

A precise intended purpose includes:

  • The medical condition or disease being diagnosed, treated, or monitored
  • The intended patient population (age range, clinical context)
  • The intended user (professional healthcare provider, lay person)
  • The intended use environment (hospital, community, home)
  • Whether the device is for single use or reusable

Example of a poorly scoped intended purpose:

"For use in diagnosis."

Example of a well-scoped intended purpose:

"The XYZ analyser is intended for the in vitro quantitative measurement of glucose in capillary whole blood samples in adult patients (18 years and above) with diabetes mellitus, for use by trained healthcare professionals in point-of-care settings."

3. Intended users​

Who will use the device? Specify:

  • Lay users (patients, general public)
  • Trained healthcare professionals
  • Specialist clinicians only
  • Or a combination

The intended user affects labelling, IFU complexity, usability testing requirements, and risk assessment of use-related hazards.

4. Intended patient population​

Define the patients on/with whom the device will be used:

  • Age range
  • Clinical condition / indication
  • Contraindicated populations
  • Paediatric use (if applicable — requires specific considerations)

5. Principle of operation​

How does the device work? Describe the mechanism of action or operating principle:

  • Physical/mechanical principles
  • Chemical/biochemical principles (for IVDs)
  • Electronic/software principles
  • Energy sources used

6. Device variants and models​

List all variants, models, sizes, or configurations covered by the technical file:

  • Tabulate variants with their distinguishing characteristics
  • Confirm that all variants are covered by the essential requirements analysis and testing programme
  • Identify any variants that require separate risk assessment or testing

7. Accessories and components​

List all:

  • Accessories specifically intended for use with the device (regulated as medical devices in their own right)
  • Consumables supplied with or for the device
  • Software components (if applicable)
  • Components and parts that critically affect performance or safety

8. Materials and substances​

For devices in contact with the patient (or in contact with specimens for IVDs):

  • List materials in contact with the body or specimen
  • State the material specification standards applied (ISO, EN, ASTM)
  • Identify any substances of concern (CMR substances, endocrine disruptors, latex)
  • Reference the biocompatibility evaluation (ISO 10993)

9. Sterility status​

State:

  • Whether the device is supplied sterile, non-sterile, or both
  • The method of sterilisation (EO, gamma, electron beam, steam, etc.)
  • Sterility assurance level (typically SAL 10⁻⁶)
  • Packaging system and its relationship to sterility maintenance

10. Shelf life and storage conditions​

  • Stated shelf life (from date of manufacture)
  • Storage conditions (temperature, humidity, light, etc.)
  • In-use stability (for IVDs: opened reagent stability)

11. Single-use / reuse status​

  • Confirm whether the device is single-use or reusable
  • For reusable devices: number of reuse cycles; reprocessing instructions location (IFU)
  • For single-use devices: "Do not reuse" labelling requirement

Common issues in device description sections​

IssueImpact
Overly broad intended purposeInconsistency with clinical evidence scope; UKAB challenge
Missing variantsTechnical file may not cover all marketed products
No patient population definedRisk management and clinical evaluation left incomplete
Materials not fully specifiedBiocompatibility evaluation cannot be properly scoped
Intended user not statedUsability testing scope unclear; IFU complexity misjudged

Official references​

ReferenceDescription
UK MDR 2002, Schedule 1 (ER 18)Labelling and IFU requirements — informs intended purpose scope
UK MDR 2002, Schedule 3Technical file requirements implicit in conformity assessment
MHRA: Guidance on the UK MDR 2002General technical file guidance
ISO 13485:2016, Clause 7.3Design and development — informs technical file structure
EU MDR 2017/745, Annex IIEU technical documentation requirements (detailed comparative reference)