Normal use or predictable abuse?
Medical devices and IVD producers must have the concepts “Normal use”, “Predictable abuse”, “Errors in expected use” AND “False application” differentiate. This is the prerequisite to understand and meet the requirements of ISO 14971 and IEC 62366.
The measures that manufacturers must take also depend on the type of use.
1. Definitions and examples
1.1 Determined use
According to ISO 14971, the expected use indicates the
Use for which a product, a procedure or service is determined in accordance with the specifications, instructions and information provided by the manufacturer
According to IEC 62366-1, users can also make mistakes when using. This can be counterintuitive for some.
1.2 Noral use
Conscious action, intentional or intentional failure of making an action that opposes the expected or violating use and is also found outside of any other reasonable means of taking the risk related to the user interface by the manufacturer
IEC 62366-1: 2021, 3.1
The use is therefore abnormal if three conditions are met:
- The user acts consciously or do not deliberately recite.
- The user violates the expected use.
- The manufacturer can hardly master the associated risks.
The secret committees of the standards remains the reason why the control has been incorporated into this definition. This can mean a final risk controller, because in certain circumstances the final use is borne by the user or the organization, that the medical work has been purchased.
The standard mentions as an example of abnormal use:
- Severely negligent use
- Sabotage
- Certainly ignoring security information
The abnormal use would be available if a technician in the hospital deactivates the security alarms of a ventilation device to prevent their “disturbing trigger”.
1.3 foreseeable abuse
In addition to the term “predictable abuse”, there is also talk of predictable improper use “.
ISO 14971 requires producers to “reasonably document predictable abuse”. Now it provides a definition of “reasonably predictable improper use”.
The use of a product or system in a way that was not understood by the manufacturer, but can derive from an easily predictable human behavior
Your EN ISO 14971: 2022 3.15
The standard clarifies that this improper use can be performed on purpose or involuntarily.
The DIN EN 82079-1 provides a similar definition.
Application of a product in a way that is not intended for the manufacturer or supplier, but this can derive from predictable human behavior
DIN EN 82079-1
There is no strong separation between predictable and unpredictable. The probability of this action is crucial.
Once an action has occurred, an action should be classified as “reasonably predictable”.
Post-market surveillance (market monitoring) helps identify these actions because they also documents them.
An example of “predictable abuse ” It would be a patient who uses the same blood sugar measurement device, but would share the blood sampling lanzette with other family members, although the instructions for use expressly indicate that the hands are intended only for a time use.
An example of “Non -foreseen abuse“It would be a surgeon used for an experimental micro-neurosurgery for which it is neither designed nor suitable for use in general surgery.
This application is so far from the expected use and is so unusual that it could not have been significantly foreseen by the manufacturer.
1.4 Short version
IEC 62366-1 and ISO 14971 standards work with different taxonomies:
1.4.1 Tassonomy The IEC 62366-1
IEC 62366-1 initially differs between expected and abnormal use.
The IEC 62366 does not “normally” differentiate between predictable and not pre -predictable abuse. However, in Appendix D says that no rule can examine non -visible actions.
IEC 62366-1: 2015 no longer knows the taxonomy of the wrong idea with a preliminary form (see Fig. B.1). One of the reasons is that the distinctions in taxonomy classes were not always separated and useful. For example, if a user inserts a laboratory value in mmol/l instead of the expected mg/dl because it did not seem correctly (attention error) or because the difference was not clear (error) often led to discussions. Of course, the measures that minimize the risk can differ.
1.4.2 ISO 14971 taxonomy
On the other hand, ISO 14971 distinguishes between reasonably predictable and reasonably not prevalent abuse. However, he does not know the concept of abnormal use.
2. Relating framework
2.1 Scope of application of the standards
Neither ISO 14971 nor IEC 62366-1 require to consider the abuse reasonably not prevention.
The abnormal use is located outside the application area of the EIC 62366-1. If the abnormal use is predictable, it belongs to the scope of ISO 14971.
The reuse of the lanzette described above must be considered in risk management according to ISO 14971. However, it is not the subject of IEC 62366-1. Furthermore, this does not have the obligation to describe a corresponding “use scenario”.
ISO 14971 also looks at the “evil user” who could abuse the medical device (predictable!). This abuse could be that the user uses it for non -advanced purposes, deliberately ignore the safety instructions or uses it without adequate training, although this is explicitly requested.
IEC 62366, on the other hand, starts from the “good user”. He only looks at the errors that derive from the fact that the user forgets something, is inattentive or undermining it.
In the case of an error, the user acts for the complete (and good) intent, but endangers a patient or a user. This could happen, for example, because it has misunderstood the product. The standard speaks of a “wrong mental model”.
The foreseeable abuse can be found in Figure 2 in the “Use error” box and “predictable abnormal use”.
2.2 MDR and IVDR requirements
MDR and Ivdr require that producers minimize the risks through the errors of the application (Appendix I, section 5). Post-market surveillance producers also take on. Part of this monitoring after positioning on the market should affect the use of products.
2.3 ISO 14971 requirements
The international standard for risk management (ISO 14971) requires that a manufacturer not only ScopeBut also the Reasonably predictable abuse must document. It must consider both the analysis of the risk and to take appropriate measures. THE Abuse reasonably not visible He doesn’t have to look. However, the manufacturer can act through protective mechanisms and IFU warning.
2.4 Requirements of IEC 62366-1
IEC 62366-1 obliges manufacturers to identify usability risks, adopt measures and evaluate the effectiveness of these measures in the training and hummative assessments.
2.5 Requirements of IEC 60601-1
Manufacturers must ensure that medical devices meet the applicable requirements of the EIC 60601-1 also with foreseeable abuses.
3. Summary and conclusion
3.1 Concept definitions against -active and blurred
Not all the terms considered here are intuitive.
- Many include abuse to act in bad intentions. But this does not coincide with the definitions.
- Furthermore, the predictability of an action has nothing to do with the fact that it is deliberately or involuntarily committed. Here the terms and understanding of two rules collapse which are not well coordinated.
- Many set “conceivable” and “predictable”. IEC 62366-1 knows only “predictable”.
- An expected use may be available, even if you make a “use error”.
3.2 Not predictable or not expected?
The declaration of IEC 62366-1: 2015 can be accepted that a standard cannot treat incredible actions. Here you should clearly distinguish if you don’t look for something or if you refuse something as not predictable.
3.3 Conclusion
A precise and uniformly defined term are needed in all relevant rules to avoid discussions and create precise documentation. If, due to the complexity of the relationships between the terms, explanatory explanations are necessary, this should not be done by “notes” so called, but it should be done in the information attacker possible by memorable examples. Here the standards still have a little recovery.
Change the story
- 2025-03-25: This new contribution replaces two obsolete contributions to “predictable abuse” and “abnormal use”.
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Medical devices and IVD producers must have the concepts “Normal use”, “Predictable abuse”, “Errors in expected use” AND “False application” differentiate. This is the prerequisite to understand and meet the requirements of ISO 14971 and IEC 62366. The measures that manufacturers must take also depend on the type of use. 1. Definitions and examples 1.1…