Which medical devices require instructions for use?
In the EU, and according to the Medical Device Regulation (2017/745 MDR Annex I, 21.1 d)), class I and class IIa medical devices that can be used safely are not required to include instructions for use. This means that a vast majority of medical devices should and would have instructions for use.
What to consider when writing instructions for use
The instructions for use is the output of multiple processes, considerations and requirements. The seven top things to consider when writing instructions for use for medical devices are:
- The intended use
- The usability engineering process
- The risk management process
- General safety and performance requirements
- Legal requirements
- Product requirements
The intended use
The intended use is a cornerstone in what you as a manufacturer have to say about your medical device. It is defined as:
use for which a product, process or service is intended according to the specifications, instructions and information provided by the manufacturer. “
– ISO 14971:2019, 3.6
Make sure to adjust the language to the relevant audience. If your users are doctors, you may or even should use a different language compared to if your medical device is intended to be used by laypeople with varying cognitive abilities.
Your instructions for use should be aligned with the intended use that you defined in the beginning of the process and that your clinical evaluation or regulatory approvals address.
The usability engineering process
Strictly speaking, usability engineering from a regulatory point of view and the 62366-1:2015 standard “…strictly focuses on applying the usability engineering process to optimise the medical device usability as it relates to safety. “ (p. 6).
This means that you can use the usability engineering process as well, to achieve user-friendliness even though the safety and efficacy of your product may not depend on it. The IEC 62366-1 standard is state-of-the-art in the EU and a recognised consensus standard by the FDA. In this standard, user interface is defined as:
Means by which the user and the medical device interact.
Note 1 to entry: Accompanying documentation is considered part of the medical device and its user interface.”
– IEC 62366-1, 3.26
The above definition means that the instructions for use is a part of the user interface and shall be addressed by the usability engineering process. The usability engineering process identifies characteristics of medical device users and patients that could result in use errors and hazard-related use scenarios. This could be the result of users’ physical and cognitive abilities and/or limitations.
Use specification and risk management that is thoroughly performed will provide input to which information should go into your instructions for use, as well as any requirements on that information and on how it should be presented.
The risk management process
The usability engineering process can be seen as a subset of the risk management process, where the overall goal is to ensure that the medical device can be used safely; that is without any unacceptable risks.
The usability engineering process focuses on the user interface and safety, as defined above, whereas the risk management process covers all life-cycle phases and aspects of the medical device. This includes both risks from normal use as well as reasonably foreseeable misuse.
The ISO 14971:2019 standard on risk management is state-of-the-art in the EU and a recognised consensus standard with the FDA. ISO 14971:2019 includes three risk control options. The last one, and the least effective, is “…information for safety and, where appropriate, training to users.” (p. 13)
Admittedly, putting a warning in the instructions for use is not an effective way of reducing risk. If you are going to rely on information for safety to reduce risk, at least put the information on the product, which is likely to have more effect. If you do put it on the product, make sure to repeat this information in the instructions for use, or explain any symbols that have been used.
Disclosing residual risks are required both by the ISO 14971:2019 standard as well as the Medical Device Regulation (2017/745 MDR Annex I, 21.1 (g)). The easiest way to explain disclosure of residual risk is to compare it to side-effects that most understand when used in conjunction with pharmaceuticals.
Residual risks are risks that cannot be further reduced by the manufacturer or by the user. Any remaining residual risks should be published in the instructions for use to ensure that the user can make an informed decision on whether he or she wants to use the device or not given the potential benefits versus risks.
Standards and guidance documents
When creating instructions for use, there are two standards in particular that you need to look at. These are the EN 1041:2008 and EN ISO 15223-1:2016 standards. The EN 1041:2008 standard contains information to be supplied by the manufacturer and the 15223-1 contains symbols used on medical devices.
The EN 1041 standard is going to be obsolete with the publication of ISO 20417. EN 1041 and the ISO 20417 specifically describes information that must be provided by the manufacturer, and would most often be found in the instructions use. The 15223 standard contains symbols that would usually be found on the medical device itself, particularly on the label. Even so, the symbols should be explained in the instructions for use.
Other standards provide symbols that should be found on the type label of the device as well, and therefore also in the instructions for use, for example the 60601 standard. Furthermore, some of the particular standards of the 60601 series will define primary operating functions, which in turn will be input to the usability engineering process. This will then provide input to the risk management process, which in turn provides input to creating the instructions for use.
The FDA has issued guidance documents on labelling and how to write instructions for users according to best practices. See for example Guidance on Medical Device Patient Labeling and Recommendations for Developing User Instruction Manuals for Medical Devices Used in Home Health Care. They are excellent guides to have when writing instructions for use and a must for anyone trying to write instructions for use for medical devices.
General safety and performance requirements
The mandatory general safety and performance requirements found in Annex I of the Medical Device Regulation contains several sections specifying information that must be found in the instructions for use. It requires you to include, for example:
- the name or trade name of the device
- the name, registered trade name or registered trade mark of the manufacturer and the address of its registered place of business
- where applicable, an indication that the device contains or incorporates:
- a medicinal substance, including a human blood or plasma derivative, or
- tissues or cells, or their derivatives, of human origin, or
- tissues or cells of animal origin, or their derivatives
For a full list of the contents required see MDR Annex I.
And lastly, the instructions of use should carry the CE mark, assuming that the product has been placed on the market other than as an investigational device.
The instructions for use are usually full of trademarks and other aspects that a legal department may have opinions about. You may, for example, include various types of disclaimers and communication that is relevant to the legal relationship between the customer and the legal manufacturer.
You may also include copyright statements to prohibit unauthorised copying and distribution of the instructions for use.
Lastly, the results of the design verification will, in most cases, confirm that the developed medical device lives up to the design inputs that were established at the onset of the project.
If so, several of those design inputs may be included in the product specification, giving the user information on things such as:
- operating temperatures
- accuracy of measurements
- EMC an immunity
- other important technical aspects
Even though some would boldly state that “…no one reads the instructions for use anyway, it’s only for going to court”, it is a painstaking task to write good instructions for use.
There are plenty of examples of the contrary. An increasing focus on usability makes it important to spend the necessary time and knowledgeable resources to author, review, approve, verify and validate the instructions for use.
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