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Medical Devices: Scope and Definitions

NIC Document


This guide explains what is meant by the term ‘medical devices’ and explains the EU directives that apply to their control and supply.

In brief

  1. Background to EU directives on medical devices
  2. The Active Implantable Medical Devices Directive
  3. The Medical Devices Directive
  4. The In-vitro Diagnostic Medical Devices Directive
  5. Relevant trade associations


Medical devices are generally defined as articles intended for a medical purpose, as assigned by the manufacturer. Within the EU, regulations for the control and supply of medical devices are governed by a series of three directives, which came into effect on 1 January 1993. They are the:
  • Active Implantable Medical Devices Directive (AIMDD) 90/385/EEC
  • Medical Devices Directive (MDD) 93/42/EEC
  • In-vitro Diagnostic Medical Devices Directive (IVDD) 98/79/EEC These directives were consolidated in the UK with further amendments.

Background to EU directives on medical devices

Before the directives were introduced, each EU member state controlled the safety and marketing of medical devices in its territory in different ways. By harmonising controls within a single system, the directives enable manufacturers to avoid the need to comply with different sets of rules. They also reassure purchasers and users that devices manufactured anywhere in the EU meet common performance and safety standards. The following sections outline the aim of each of the directives. For more detailed information, you should contact the Medicines and Healthcare products Regulatory Agency (MHRA) (www.mhra.gov.uk).

The Active Implantable Medical Devices Directive (AIMDD) – 90/385/EEC

This directive covers all powered implants or partial implants that are left in the human body. It defines an active implantable medical device as: ‘Any medical device which is intended to be totally or partially introduced, surgically or medically, into the human body or by medical intervention into a natural orifice, and which is intended to remain after the procedure.’ According to the directive, a device is ‘active’ if it functions using a source of electrical energy or any source of power other than that directly generated by the human body or gravity. Examples of types of devices covered by this directive include:

  • Implantable defibrillators
  • Leads, electrodes, adaptors for the above
  • Implantable nerve stimulators
  • Cochlear implants
  • Catheters, sensors for active drug administration devices

The Medical Devices Directive (MDD) – 93/42/EEC

This directive covers most other medical devices, ranging from first aid bandages and walking frames, to CT scanners, X-ray equipment, and non-active implants. It defines a medical device as: ‘Any instrument, apparatus, appliance, material, or other article, whether used alone or in combination, including the software necessary for its proper application intended by the manufacturer, to be used on human beings for the purpose of:

  • Diagnosis, prevention, monitoring, treatment or alleviation of disease
  • Diagnosis, monitoring, treatment, alleviation of, or compensation for, an injury or disability
  • Investigation, replacement or modification of the anatomy or of a physiological process
  • Control of conception. and which does not achieve its principal intended action in or on the human body by pharmacological, immunological, or metabolic means, but which may be assisted in its function by such means.’

The directive includes a classification system in which the level of regulatory control applied to a device is proportionate to the degree of risk associated with it. MHRA Bulletin 10, The Classification Rules (February 2006) helps to define which classification your product fits into.

The In-Vitro Diagnostic Medical Devices Directive (IVDD) - 98/79/EEC

This directive defines an in-vitro diagnostic medical device (IVD) as: ‘Any medical device which is a reagent, reagent product, calibrator, control material, kit instrument, apparatus, equipment, or system, whether used alone or in combination, intended by the manufacturer to be used in vitro for the examination of specimens, including blood and tissue donations, derived from the human body, solely or principally for the purpose of providing information:

  • Concerning a physiological or pathological state, or
  • Concerning a congenital abnormality, or
  • To determine the safety and compatibility with potential recipients, or
  • To monitor therapeutic measures

Relevant trade associations

Apart from the rigidly defined classifications outlined above, it can be difficult to define and group the broad range of medical devices. Within the UK, trade associations that deal with general and specific device/equipment types may provide further support:

Association of British Healthcare Industries (ABHI): General coverage of the medical device and healthcare industry with membership covering 700 product types. Find out more at: www.abhi.org.uk.

British In-Vitro Diagnostics Association (BIVDA): Covers all companies producing in-vitro testing equipment, with particular interest in diabetes, heart disease, osteoporosis, gastric ulcers, and cancer. Find out more at: www.bivda.co.uk.

British Healthcare Trades Association (BHTA): Covers industry associated with assistive technologies and rehabilitation, such as wheelchairs, stairlifts, stoma and continence products. Find out more at: http://www.bhta.net.

BAREMA Trade Association for Anaesthetic and Respiratory Equipment: Its website lists over 60 product types. Find out more at: http://www.barema.org.uk.