Recently, the Medical Device Technical Review Center of the State Food and Drug Administration (hereinafter referred to as the Device Review Center) issued the "Guiding Principles for Medical Device Usability Engineering Registration Review" (hereinafter referred to as the "Guiding Principles"). The "Guiding Principles" apply to the registration application for Class II and Class III medical device availability projects (not applicable to in vitro diagnostic reagents). It explains in detail eight parts including basic principles, user interface verification and confirmation, and provides standards for registration applicants. Provide guidance in carrying out medical device usability engineering work. Subsequently, the website of the Device Review Center published an interpretation article to comprehensively introduce the preparation background, scope of application, main concepts, etc. of the "Guiding Principles".

 1. Preparation background

 Medical devices require human-computer interaction to achieve their intended use, which is one of the distinctive features of medical devices. Relevant data show that the use of medical devices is a prominent problem and the risks of use cannot be ignored. The main reason is that there are problems with the availability of medical devices.

 Medical device regulatory agencies in the United States, the European Union and other countries and regions have issued a number of usability guidelines and standards in recent years, gradually strengthening medical device usability supervision. my country will officially implement the GB9706.1-2020 series of standards on May 1, 2023. This series of standards also clarifies requirements related to the availability of medical devices.

 In order to promote the smooth implementation of the GB9706.1-2020 series of standards, systematically improve China's medical device availability regulatory requirements, and further enhance China's international influence in the corresponding regulatory fields, the Device Review Center has formulated the "Guiding Principles for Medical Device Availability Engineering Registration Review" ( (hereinafter referred to as the "Guiding Principles").

 2. Scope of application

 The "Guiding Principles" apply to the registration application for Class II and Class III medical device availability projects, but do not apply to in vitro diagnostic reagents. Registration applicants can refer to the "Guiding Principles" to carry out usability engineering work for all medical devices.

3. Main Concepts

Medical device usability engineering refers to the design and development of medical devices by comprehensively applying knowledge about human anatomy, physiology, psychology, behavior, culture and other aspects of capabilities and limitations to enhance the usability of medical devices.

Usability refers to the user interface characteristics that ensure the safety, effectiveness and ease of use of medical devices when the intended user uses the medical device normally in the expected use scenario. The core elements of usability include users, use scenarios and user interfaces, focusing on the safety and effectiveness of normal use of medical devices.

Users refer to all personnel who interact with medical devices as specified by the registrant, and can be divided into multiple user groups based on user characteristics. The "Guidelines" focus on users/user groups who operate medical devices for their intended use, such as medical staff, patients, and home care, including medical device disinfection and sterilization operators.

Use scenarios refer to the scenario factors for the actual use of medical devices specified by the registrant, including the use environment and operation tasks. The use environment refers to the actual environment in which users operate medical devices, including the use site and environmental conditions; the operation task refers to the actions or action sequences of users operating medical devices to achieve specific goals, which can be divided into critical tasks, emergency tasks, and common tasks. The Guiding Principles focus on operational tasks related to medical activities, based on key tasks, especially key tasks that are also emergency tasks and common tasks.

User interface refers to all objects and methods of human-machine interaction between users and medical devices, including but not limited to the shape, size, weight, display, feedback, connection, assembly, operation, control, instructions, labels, packaging, user training materials, etc. of medical devices.

Normal use means that users operate medical devices in accordance with the requirements of the instructions and common sense practices, otherwise it is abnormal use. Normal use can be divided into correct use and incorrect use from the perspective of use results. Correct use refers to normal use without incorrect use; incorrect use refers to user actions or lack of actions that result in medical device responses that are different from those expected by the registrant or user.

The actual use of medical devices is relatively complex and can be subdivided into correct use, difficult use, dangerous use, and incorrect use, which refer to use that meets expectations, use that is lower than expectations but meets requirements, use that almost presents unacceptable risks, and use that does not meet expectations or is not completed. Among them, difficult use can be improved according to specific circumstances, dangerous use requires preventive measures, and incorrect use requires corrective measures.

4. Core Ideas

The Guiding Principles focus on the design of user interfaces for medical devices and consider the requirements for usability engineering from the perspective of medical device design and development. Differentiate regulatory requirements based on the risk level of medical device use: In principle, high-risk medical devices need to carry out complete usability engineering life cycle quality control and submit usability engineering research reports; medium and low-risk medical devices can carry out usability engineering life cycle quality control based on the risk management process and submit use error assessment reports.

Considering the actual situation of the industry, high-risk medical devices are currently managed according to the catalog, including 19 types of Class III medical devices. The remaining Class III and all Class II medical devices are managed as medium and low-risk products.

Medical device usability engineering is an important part of medical device design and development. Registrants need to establish a sufficient, appropriate and effective usability engineering process within the framework of the quality management system design and development process, referring to the corresponding content of the Guiding Principles or usability-related standards. Annex 1 of the Guiding Principles provides an introduction to common methods of usability engineering, and Annex 2 provides basic elements of usability engineering for reference by registrants.

5. User Interface Verification and Validation

User interface verification and validation is an important part of medical device design verification and validation, that is, user interface verification belongs to design verification, and user interface validation belongs to design validation. From the perspective of usability engineering, user interface verification is also called formative evaluation, and user interface validation is also called summative evaluation.

User interface verification can adopt or combine methods such as expert review, cognitive walkthrough, and formative usability testing. User interface validation can adopt or combine methods such as summative usability testing and comparative evaluation of equivalent medical devices. In principle, new products adopt summative usability testing; mature products can adopt comparative evaluation of equivalent medical devices.

Usability testing refers to user interface evaluation based on observation data and interview data of expected users completing operation tasks in the expected use environment, that is, user interface testing conducted in simulated use environment and real use environment. Registrants can use simulation testing (based on simulated use scenarios, based on self-built usability laboratories), on-site testing (based on real use scenarios) to conduct summative usability testing, and can also entrust third-party usability laboratories (including testing institutions, universities, research institutions, etc.) to conduct summative usability testing.

Equivalent medical devices refer to similar medical devices that are basically equivalent to the declared medical devices in terms of the intended use, applicable population, structural composition, users/user groups, user characteristics, places of use, environmental conditions, key tasks, human-computer interaction methods, user training, etc., and have been registered and marketed in China. The applicant can refer to the comparative clinical evaluation method of the same variety, and conduct comparative evaluation of equivalent medical devices in combination with the differences between the declared medical devices and equivalent medical devices and the new use risks.

VI. Relationship with clinical trials

Certain key task test items of user interface confirmation test may cause serious harm or death to the subjects and cannot be performed in clinical trials. At the same time, the user interface confirmation test has clear requirements for the number of test participants, and the number of participants in clinical trials may not meet the corresponding requirements. Therefore, clinical trials cannot usually replace user interface confirmation tests, but can serve as support and supplement to the latter.

In special cases, clinical trials can be used as user interface confirmation tests if they meet the requirements of summative usability tests.

7. Imported medical devices

 There are differences between China and foreign countries in terms of users and usage scenarios of imported medical devices, and there are also differences in registration and declaration requirements for usability projects between China and foreign countries. Therefore, in principle, imported medical devices need to carry out corresponding user interface confirmation work in China based on the level of use risk, unless supporting materials with detailed data are provided to prove that differences between China and foreign countries have no significant impact on user interface confirmation.

 For high-risk medical devices, registration applicants need to conduct a difference analysis of Chinese and foreign usability engineering based on users, usage scenarios and registration application requirements, submit corresponding usability registration application materials based on the difference analysis results, and conduct user interface re-confirmation when necessary.

 For medical devices with medium or low risk of use, registration applicants only need to submit a use error assessment report and overseas marketing usability engineering research materials.

 8. Ready-made user interface

 Ready-made user interface refers to a user interface for which the registration applicant has not conducted (including cannot prove) complete usability engineering life cycle control.

 The safety and effectiveness of ready-made user interfaces can be confirmed by referring to the comparative evaluation method of equivalent medical devices, focusing on analyzing the post-market use issues of ready-made user interfaces. If it cannot be confirmed, you need to reconfirm according to the requirements of the self-developed user interface.

 Medical devices can use multiple ready-made user interfaces. On the basis of confirming the safety and effectiveness of each ready-made user interface, the safety and effectiveness of all user interfaces must be confirmed from the overall perspective of the medical device product.

 9. Combined use

 If an active host and special active accessories, active equipment and special passive consumables, active equipment and special test kits, medical devices and drugs can be used in combination to achieve the intended purpose, the registration applicant needs to conduct an overall review from the medical device system level. User interface confirmation, submit the usability engineering research data of the medical device system in the respective registration unit, or submit the corresponding usability engineering research data according to the use risk level.

 10. Availability Engineering Changes

 Medical device usability engineering changes must be carried out in accordance with the requirements of the quality management system, and appropriate usability engineering verification and confirmation activities must be carried out, while its impact on the safety and effectiveness of the medical device must be assessed.

 Substantial changes to the user, usage scenario, and user interface of a medical device require, in principle, application for change registration. Other usability engineering changes are controlled through the quality management system and do not require application for change registration.

XI. Usability Engineering Research Materials

Usability engineering research materials are divided into usability engineering research reports and use error assessment reports.

Usability engineering research reports are applicable to high, medium and low use risk medical devices, including basic information, use risk level, core elements, usability engineering process, user interface requirement specifications, use risk management, user interface verification and confirmation, user interface traceability analysis, user training programs, conclusions and other contents.

Use error assessment reports are used to refine the content of the risk management report on usability, and are only applicable to medium and low use risk medical devices, including basic information, use risk level, core elements, analysis of use problems of similar medical devices after listing, use risk management, conclusions and other contents.

For high use risk medical devices, submit a usability engineering research report. For medium and low use risk medical devices, submit a use error assessment report; if usability engineering work has been carried out in the early stage, a usability engineering research report can also be submitted to replace the use error assessment report.

XII. Application instructions

From October 8, 2024, medical device products to be submitted for application shall submit corresponding usability registration application materials according to specific circumstances, and medical device products under review do not need to submit usability registration application materials.

For medical device products to be registered, high-risk medical devices shall submit usability engineering research reports. For medium- and low-risk medical devices, if the corresponding product guidelines have usability or usability-related requirements, the corresponding registration application materials shall be submitted as required. In other cases, a use error assessment report shall be submitted.

For medical device products to be registered for change, it is not necessary to supplement the usability engineering research materials of the product before the change. If it involves substantial changes in users, usage scenarios, and user interfaces, the usability registration application materials shall be submitted in accordance with the requirements of the preceding paragraph.

For medical device products to be registered for renewal, in principle, it is not necessary to submit usability registration application materials.