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On November 1999, the Institute Of Medicine published “To Err Is Human”, a report analyzing the mortality of people in hospitals in the United State (up to 98000 deaths) as a result of medical errors, laying out strategies to “reduce preventable medical errors”. As per this report, medical errors, more commonly “are caused by faulty systems, processes, and conditions that lead people to make mistakes or fail to prevent them.” 

If a device is difficult to use, or the instructions are not understandable for the user, device is more likely to be used incorrectly.  Poor design of medical devices and specifically poor user interface design can lead to errors that can deter patient treatment, diagnostic or monitoring and in some cases can result in harm or death; examples such as administration of incorrect medication or dose, incorrect interpretation of data resulting in misdiagnosis and also incorrect device setting for therapy are proofs of poor user interface design.

Medical Device Usability Highlights European Regulations Standards

Usability and Human factors

Usability Standards, IEC 62366:2007, IEC 62366:2007+A1:2014, IEC 62366-1:2015, define Usability as characteristic of the user interface that establishes effectiveness, efficiency, and user satisfaction. Therefore, In order to minimize use errors and use associated risks, reasonable Usability must be achieved by using usability Engineering process. (IEC 62366:2007 and A1:2014).

It should be noted that the term Usability engineering and Human factors engineering are treated synonymously by Usability standards, EN 62366:2008 and NF EN 62366-1:2015. Also as per USA FDA “Introduction to Human Factors in medical Devices”, the terms "human factors engineering,” "usability engineering and ergonomics" are often used interchangeably for the process utilized to achieve highly usable equipment.

Human Factors, however is defined as “discipline that seeks to improve human performance in the use of equipment by means of hardware and software design that is compatible with the abilities of the user population” (USA FDA, An Introduction to Human Factors in medical Devices, Dec. 1996).

Medical Device Usability Standards

The main standard of usability to be used for medical devices intended to be sold to the European market is EN 62366 (Medical devices-Application of usability engineering in medical devices) which is the European harmonized standard adopted from the international standard, IEC 62366. This is a process based standard for analysis, design, verification and validation of usability through the development cycle of the medical devices as it relates to their safety.

For medical electrical equipment, there is also the collateral standard EN 60601-1-6. However edition 2010 of this standard (clause 4.2) states that “usability engineering process complying with the IEC 62366 shall be performed”; therefore EN 62366 is adopted as the main standard for demonstration of usability of all medical devices.

The requirements of the standards are the same in the IEC and EN versions, therefore when IEC 62366 is used in the following section; it also applies to EN 62366.

Usability standards, the latest Edition

On February 2015 Part 1 of the latest version of IEC 62366, “Application of usability engineering to medical devices” was officially published. On April 2016, part 2 of the same standard, IEC/TR 62366-2, “Guidance on the application of usability engineering to medical devices” followed the first part. The main purpose of each part is described below:

 IEC 62366-1:2015 (Part 1)  IEC/TR 62366-2:2016 (Part 2)

Mainly focusing on the usability engineering as a design and development process for the medical device user interface to identify and reduce the possibility of use errors and use associated risks. This part of the standard targets only the safety-related part of the usability of medical devices.

Technical report discusses Information about efficient ways to implement elements required by IEC 62366-1: 2015 and also additional information on how usability relates to attributes such as Task efficiency and User satisfaction which can enhance a medical device commercial success.

This Technical report does not contain any requirements; however it is intended to be read in conjunction with IEC 62366-1:2015



IEC 62366-1: 2015 is not yet harmonized and does not appear on the list of the Official Journal of the European Union, therefore the latest European harmonized standard is still EN 62366: 2008 (equivalent to IEC 62366: 2007). It should also be noted that the amendment to this standard (EN 62366/A1: 2015) is not harmonized as of today.  On the contrary, IEC 62366-1: 2015, has been recognized by the FDA as of August 2015 in replacement of IEC 62366: 2007.

Manufacturers marketing both in Europe and the United States may decide to apply the new standard to show compliance, as it demonstrates compliance with the essential requirements as well as the previous version, whereas IEC 62366: 2007 is no longer recognized by the FDA.  In this case the manufacturer may document a rational in the Summary Technical file that justifies compliance with EN 62366:2008 while using IEC 62366-1:2015. 

Usability and European Essential Requirements

The European Regulation addresses the usability requirements in order to minimize and reduce user/use errors and user/use associated risks in the general essential requirements of medical device directives. The applicability of usability harmonized standards for each directive is shown below:

Directive  93/42/EEC :  EN 62366   & EN 60601-1-6 (Medical electrical equipment)
Directive  98/79/EC : EN 62366  N/A 
Directive  90/385/EEC : N/A  EN 60601-1-6


Annex I of medical device Directive 93/42/ EEC address specific usability concerns:

ER 1 -- The devices must be designed and manufactured in such a way that, when used under the conditions and for the purposes intended, they will not compromise the clinical condition or the safety of patients, or the safety and health of users or, where applicable, other persons….this shall include:


— reducing, as far as possible, the risk of use error due to the ergonomic features of the device and the environment in which the device is intended to be used (design for patient safety)
— consideration of the technical knowledge, experience, education and training and where applicable the medical and physical conditions of intended users (design for lay, professional, disabled or other users)

ER 9.2– Devices must be designed and manufactured in such a way as to remove or minimize as far as possible: — the risk of injury, in connection with ….appropriate ergonomic features

ER 10.2 – The measurement, monitoring and display scale must be designed in line with ergonomic principles, taking account of the intended purpose of the device

ER 11.4.1 –operating instruction avoiding misuse for devices emitting radiation

ER 12.9 – device instructions required for its operation must be understandable to the user and patient

ER 13.1 – accompanying documents taking account of the training and knowledge of the potential users

Other Essential Requirements with a link to Usability are 2, 3, 6, 12.8 and 12.9


For Directive 98/79/EC, similar provision can be found in Annex I ER B. 3.3; 3.6; …

Usability and Regulation (EU) 2017/745

By May 26th 2020 all manufacturers aiming to market their medical devices within the EU will be required to conform to the Medical Device Regulation (EU) 2017/745. As like todays practice, manufacturers can choose to comply with the harmonized standard to show the conformity with the regulations.  Medical Device Regulation addresses Usability concerns in different sections as below:

Chapter VII, Post Market Surveillance, Article 83, point f: Data gathered by the manufacturer's post-market surveillance system shall in particular be used for the identification of options to improve the usability, performance and safety of the device

Article II, Definitions, “Incident”: incident means any malfunction or deterioration in the characteristics or performance of a device made available on the market, including use-error due to ergonomic features, as well as any inadequacy in the information supplied by the manufacturer and any undesirable side-effect;

ANNEX I, Chapter I, General Requirements:

GR 5: In eliminating or reducing risks related to use error, the manufacturer shall:(a) reduce as far as possible the risks related to the ergonomic features of the device and the environment in which the device is intended to be used (design for patient safety)

GR 14.2: Devices shall be designed and manufactured in such a way as to remove or reduce as far as possible: (a) the risk of injury, in connection with their physical features, including the
volume/pressure ratio, dimensional and where appropriate ergonomic features;

GR 14.6: Any measurement, monitoring or display scale shall be designed and manufactured in line with ergonomic principles, taking account of the intended purpose, users and the
environmental conditions in which the devices are intended to be used

Similar provisions can be found in Annex I GR5; GR13.2; GR 13.7; … of In Vitro Diagnostic Medical Device Regulations (EU) 2017/746.

Legacy User Interface or User Interface of Unknown provenance (UOUP)

A normative annex has been added to the Amendment 1 of standard EN 62366:2008 (Annex K) and lately to the EN 62366-1:2015 (Annex C) to address requirements of medical devices with User Interface of Unknown Provenance (UOUP) such as the interface of a previously designed medical device for which records of the user interface process are not available.

However since EN 62366-1:2015 considers usability engineering  as  part of the product development process, it should be noted that if the user interface or part of the user interface were not developed using the processes of this standard, they are considered as unknown provenance with respect to these processes. Requirements of Annex K (EN 62366/A1: 2015) and Annex C (EN 62366-1:2015) replace the requirements of clauses 5.1 to 5.9 to evaluate the UOUP mainly focusing on:

  • Documentation of use specifications and main service functions
  • Post-production information Review
  • Risk management file review
  • Review of accompanying documents

NF EN 62366-1:2015 Overview:

The 50 pages of the new standard are broken up to 3 main different parts: 1. Body of Standard (Scope; Normative References; Terms and Definitions; Principles; and Usability Engineering Process), 2. Informative annexes (A, B, D and E) and 3. Normative annex C.

While the basic overall structure is similar to the previous editions, the new edition streamline the Usability engineering process and strength the link with the risk management ISO 14971:2007.

The main elements of the NF EN 62366-1:2015 comparing to EN 62366:2008 are listed below:

Cl. 4.1.1

General requirements for personal competency regarding usability engineering activities is added

Cl. 4.1.2

Specification of requirements of risk control related to user interface design: a 3-level approach as required by NF EN ISO 14971

Cl. 4.3

Specification of elements tailoring the usability engineering effort such as complexity of user interface and use specification, severity of the harm,  presence of UOUP.

Cl. 5.2

Clarification of requirements to identify user interface characteristics related to safety and use errors

Cl. 5.3

Specification of elements to consider to identify hazardous situation such as use specification, existing user interface and use errors

Cl. 5.4 & 5.5

Identification of use scenarios that could lead to harm and considering them during summative evaluation

Cl 5.6

Clarification of user interface specification requirements: consideration hazard related scenarios, determination of the necessity of accompanying documents and training

Cl. 5.7

Specification of user interface evaluation plan  (objectives and methods of formative and summative evaluation, documentation of usability test parameters (users, environment, documentation, training)

Cl. 5.8 & 5.9

Evaluation of user interface: design, implementation and formative evaluation (iteratively during design and development process to explore unanticipated use errors), summative evaluation (at the end of user interface development, part of verification and validation of the overall medical device design to conclude that User Interface can be used safely)


“Formative Evaluation” and “Summative Evaluation”


“Frequently Used Functions”


“Usability Verification”


Number of informative annexes reduced to 3 . UOUP formative annex remained as Annex K


Risk Management and Usability:

Application of Risk management to medical devices (ISO 14971:2007, EN ISO 14971:2012) is normatively referenced in EN 62366-1:2015 and is essential for its application.  Risk management is in fact a decision making process to determine acceptable risks and all risks rising from usability have to be evaluated by Risk management. However, Usability Engineering as a design and development process, evaluate the usability and mitigate the use errors that could results in risks for medical devices. The flowchart below illustrates steps of usability engineering process as defined in part 1 of EN62366:2015 and  its relationship with applicable parts of risk management process (EN ISO 14071:2007) as referenced in Figure A4 of the above usability standard.

Usability Risk Management Diagram


Usability and Medical device Quality Management System

Medical device Quality management system standards clearly added the usability requirements to the design and development section in the latest version of EN ISO 13485: 2016 in 2 clauses:

  • Cl. 7.3.3 a: Usability and safety requirements according to the intended use shall be determined and recorded as an input for design and development
  • Cl. 7.3.9: Significant of the change to usability for medical devices and its intended use shall be determined as part of control of design and development changes

NF EN 62366-1: 2015/EN 62366:2008: outcome

As per Usability Standards (IEC 62366:2007, IEC 62366:2007+A1:2014, IEC 62366-1:2015), all aspects of usability engineering process should be documented in a Usability engineering file.

Usability engineering file could be an independent file, part of risk management file or part of product design file. It may also contain pointers and references to all required documents. The usability engineering file enables efficient auditing of the design and development process.


LNE DOWNLOAD PDF  Download this newsletter in pdf format here.


Sara Jafari LNE Gmed

Topic: Usability for Medical Devices: Highlights of the European Regulations and Standards
Date: Wednesday, August 30th, 2017
Time: 2:00 - 2:30 PM EDT

About the presenter: Dr. Sara Jafari, Certification Project Manager at LNE/G-MED North America, Inc. 
Click here to Register!

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