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What is a Medical Device?


In general terms, a medical device is any device that is intended for medical purposes. These devices help healthcare providers to diagnose and treat patients, helping patients to overcome illness or disease and improving quality of life.

There are potential hazards associated with the use of medical devices and so these products must be shown to be safe and effective with regulations put in place by bodies and governments around the world.

The greater the risk posed by the device, the greater the amount of testing that is usually required before a device is allowed to be used. However, it is also the case that the greater the risk, the greater the potential benefit to the patient.


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Medical Devices and TWI

TWI has years of experience in assisting medical companies to meet technological and regulatory compliance with their devices. This covers both low volume, high cost products and high volume, low cost items.

We can offer expertise in everything ranging from materials and joining through to design and prototyping. We can also help with business planning, quality management and process support.

Find out more about our services for the medical device industry

Regional Definitions

While you probably understand what a medical device is in general terms, it is difficult to establish a universal definition since different regulatory bodies across the world have their own varying definitions of what a medical device is. These subtle differences mean that the exact meaning of what a medical device is differs depending on region.

However, medical devices are generally differentiated from drugs, since the regulatory requirements between the two are different. There is also some crossover, such as with in vitro diagnostics, which are generally seen as a subclass of medical devices.

For example, to understand these differences, here are the official EU and US definitions for medical devices:

EU Definition

The European Union classes medical devices in Article 1 of Council Directive 93/42/EEC, as any

"instrument, apparatus, appliance, software, material or other article, whether used alone or in combination, including the software intended by its manufacturer to be used specifically for diagnostic and/or therapeutic purposes and necessary for its proper application, intended by the manufacturer to be used for 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 handicap,
  • 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;"

United States (Food and Drug Administration)​ Definition

Section 201(h) of the Federal Food Drug & Cosmetic (FD&C) Act defines a device as an

"instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, including a component part, or accessory which is:

  • Recognised in the official National Formulary, or the United States Pharmacopoeia, or any supplement to them
  • Intended for use in the diagnosis of disease or other conditions, or in the cure, mitigation, treatment, or prevention of disease, in man or other animals, or
  • Intended to affect the structure or any function of the body of man or other animals, and
  • which does not achieve its primary intended purposes through chemical action within or on the body of man or other animals and which is not dependent upon being metabolised for the achievement of its primary intended purposes. The term 'device' does not include software functions excluded pursuant to section 520(o)."

The United States definition is further complicated by the fact that some products are considered to be medical devices in some jurisdictions but not in others, including disinfection substances, aids for people with disabilities, devices that incorporate animal and/or human tissues, and devices for in-vitro fertilisation or assisted reproduction technologies.

History and Medical Device Regulation

The earliest examples of what we would describe as a medical device date back thousands of years to Baluchistan in around 7000 BC, where Neolithic people used flint-tipped drills and bowstrings for dentistry. Archaeological finds and literature also show that various types of medical device were in use in the time of ancient Rome.

However, despite this history of use, regulation of medical devices only occurred relatively recently.

In the United States, medical devices were not regulated until 1938 with the passing of the Federal Food, Drug, and Cosmetic Act. This act was further regulated in 1976 with the Medical Device Amendments to the FD&C Act.

European device regulation as we know it today did not come into effect until 1993 with the collective Medical Device Directive (MDD), which was replaced on May 26, 2017 with the Medical Device Regulation (MDR).

The Medical Device Market

The global medical device market is worth over US$250 billion each year, with 40% of this market being controlled by the United States. Europe makes up a further 25% of this global market share, Japan 15%, and the rest of the world comprises the final 20% of the market. The European market is led by Germany, followed by Italy, France and the United Kingdom.

Medical Device Examples

As mentioned above, it can be difficult to distinguish between medicines and medical devices, for example cosmetics, food supplements, and biocidal products can fall into either category and are called borderline products until their exact status has been decided. Adding to the complexity for such combination products, these categorisations can be different in different regions of the world.

However, medical devices vary from the simple to the more complex and include anything from medical gloves, thermometers and bedpans through to pacemakers and prosthetics.

The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) categorises a medicinal product as:

  • any substance or combination of substances presented as having properties of preventing or treating disease in human beings
  • any substance or combination of substances that may be used by or administered to human beings with a view to restoring, correcting or modifying a physiological function by exerting a pharmacological, immunological or metabolic action, or making a medical diagnosis

The MHRA also determines that food supplements which contain vitamins, amino acids or minerals are labelled as foodstuffs and thereby are subject to food safety and labelling legislation rather than medicinal control.

What is a Class 1 Medical Device?

The United States Food and Drug Administration (FDA) has classified around 17,000 medical devices into 16 medical specialities known as panels. Each one of these generic devices is assigned to one of three regulatory classes based on the level of control required to assure their safety and effectiveness.

The three classes and the requirements which apply to them are:

Class I General Controls

  • With Exemptions
  • Without Exemptions

Class II General Controls and Special Controls

  • With Exemptions
  • Without Exemptions

Class III General Controls and Premarket Approval

Class 1 medical devices have a low to moderate risk to the patient or user. 47% of medical devices come under this category, with 95% of them being exempt from the regulatory process. 

Those devices that fall into that are exempted and Class 1 do not require a premarket notification application or FDA clearance before marketing the device in the U.S. However, the manufacturer is still required to register their establishment and list the product with the FDA.

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