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  • 1.  IEC 62304 Unit Testing and Integration Testing

    This message was posted by a user wishing to remain anonymous
    Posted 20-Feb-2019 08:39
    This message was posted by a user wishing to remain anonymous

    In developing a Class B software medical device (e.g. a mobile app), can a company ever justify not completing unit and integration testing and jump straight to system testing?  Thanks!


  • 2.  RE: IEC 62304 Unit Testing and Integration Testing

    Posted 21-Feb-2019 05:07
    In my humble opinion no.  Any regulator would find exception to unit and integration testing not being performed for a Class B software - even with justification.  Now depending on the complexity of the mobile app, it might be possible if was simple in design where there is really only a "system" level though need to have really good justification.

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    Richard Vincins RAC
    Vice President Global Regulatory Affairs
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  • 3.  RE: IEC 62304 Unit Testing and Integration Testing

    Posted 21-Feb-2019 07:22
    I agree with Richard.

    Even internally, this is best software practices.  If perhaps it is legacy software for which you have no clue and it wasn't done, I would still highly suggest doing it, using the 2015 version of IEC 62304.  And if it is stand-alone software that networks, look at IEC 82304 and ISO/TIR 80000-2...

    I hear this question from many small companies who didn't know what they didn't know when they started, then found out "oops" it is regulated.

    In this time of social media years of  discussions everywhere about regulation of software health apps, etc. In my opinion the " I didn't know it might be regulated" is willful ignorance. Ask somebody who can help make this determination, then follow expected standards and other best software engineering practices and DOCUMENT !

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    Ginger Cantor, MBA, RAC
    Founder/Principal Consultant
    Centaur Consulting LLC
    River Falls, Wisconsin 54022 USA
    715-307-1850
    centaurconsultingllc@gmail.com
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  • 4.  RE: IEC 62304 Unit Testing and Integration Testing

    Posted 21-Feb-2019 08:47
    Agree with Richard, with a couple of caveats (referencing 62304:2006 +AMD1:2015):

    • There is no mandate in 62304 for unit "testing".  There is a mandate for unit "verification".  In section 5.5.2, the standard seems to allow multiple means of unit verification (e.g. code review, static code analysis, unit testing), but if unit testing is chosen as the means for unit verification, then those "procedures shall be evaluated for adequacy" and would be executed using similar requirements for testing found elsewhere in the standard.
    • Although not advisable, the "Note" immediately after the text I referenced above states that it is permissible to combine integration testing and software system testing.  This does not mean that integration testing is circumvented.  It means that both activities can be consolidated, so it would be important to show in the procedures which are system tests and which are integration tests. This language is repeated in the "Integration Testing" section in Note 2 below 5.6.4.
    In my personal experience, regulators have found the overall test effort to lack some credibility if all of the defects are reported and fixed during system testing.  As a practical matter, the ability to find and fix more issues more quickly and less expensively rests, to a large extent, in the earlier phases of the development lifecycle through debugging activities, peer reviews, and unit verification activities.

    Trying to circumvent these steps, in my view, will reduce your ability to address issues closer to the point of insertion, when they are easier to find, less expensive to fix, and less impactful on other connected parts of the system.  It is also likely that much of this work is going on in an "informal" way, and the real debate is how much to document them, which brings up our old regulatory mantra, "If it isn't documented, it never happened."

    I hope this helps

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    Eric Henry
    Washington DC
    United States
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