IEC 62366 Hazard-related Use Scenario vs FDA Critical Task



1. What is the relationship between the USE SCENARIO as defined in IEC 62366 and the (CRITICAL) TASK defined in the FDA Human Factors Guidance? Is it the same or does a USE SCENARIO contain TASKS (as defined by the FDA)?
2. Similarly, what is the relation ship between a TASK as in the IEC 62366 and a TASK defined in the FDA Human Factors Guidance?
3. Consider a USE SCENARIO that contains a TASK which could lead to serious HARM (CRITICAL TASK). In my current understanding, the IEC 62366 requires to test the entire USE SCENARIO while the FDA is satisfied if the CRITICAL TASK itself is tested. Is that a correct understanding?

My understanding of IEC 62366 is that a USE SCENARIO comprises TASKS. If one of those TASKS could lead to serious HARM, the entire USE SCENARIO must be tested in the summative evaluation.
On the other hand, the FDA Human Factors Guidance requires the manufacturer to identify CRITICAL TASKS (TASKS that could lead to serious HARM). Those must then be tested in the summative evaluation.

Amongst others, the IEC 62366 defines the following terms
- TASK: one or more USER interactions with a MEDICAL DEVICE to achieve a desired result
- USE SCENARIO: specific sequence of TASKS performed by a specific USER in a specific USE ENVIRONMENT and any resulting response of the MEDICAL DEVICE

Amongst others, the FDA Human Factors Guidance defines the following terms
- TASK: Action or set of actions performed by a user to achieve a specific goal.
- CRITICAL TASK: A user task which, if performed incorrectly or not performed at all, would or could cause serious harm to the patient or user, where harm is defined to include compromised medical care.

Best Regards


Super Moderator
I'm going to give it a whirl. I'm not happy about it, but I'll try. :) Here's what we do, and so far it's been received well.

We create a Use FMEA to list all the TASKS (grouped as USE SCENARIOS such as unpacking, setup, etc.) and how they can be done wrong. If any of those could lead to harm (pre-controls), it's going to be considered for the Summative Study AND it's also considered a CRITICAL TASK and gets treatment per the HFE guidance. By and large, if there's a task in the use scenario that could lead to harm, the entire use scenario typically plays out in the summative evaluation.

Again, not saying this as gospel but it's been acceptable so far. Would welcome any critical (and constructive) feedback.


Thank you very much for sharing your approach with us. While we do not call it an FMEA but rather Task Analysis, we take the same approach by grouping TASKS into USE SCENARIOS. If any of these TASKS could lead to serious harm, that TASK is considered a CRITICAL TASK and the parent USE SCENARIO is considered for the Summative Study.
We were discussing whether it is compliant with IEC 62366 to test a stripped down version of the USE SCENARIOS in the Summative Study (i.e., the CRITICAL TASK surrounded by a few contextual TASKS that make the testing realistic), as it is our understanding that the FDA would accept this.
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