Parent Device as the Predicate for an Accessory


First I'd like to thank everyone who responds to these posts. It's my first question, but I routinely search the forums and often find what I'm looking, thanks!

The question is: how is it that the FDA has recommended I use the parent device as the predicate for an accessory, when the accessory will have a different intended use than the parent device (the needles provide access to a part of the body, and our device will prevent needle sticks)? I want to take their advice, but I'm having a hard time understanding how I'll frame the 510k submission and establish substantial equivalency when we don't meet this basic requirement.

Background: We submitted a pre-sub for a needle-stick prevention accessory for a specific set of needles. We proposed a predicate device with similar intended use from a different regulatory classification than the parent device. In their written response they responded that we *could* do that, but they recommend using the specific set of needles as the "parent predicate device." For the follow-up Pre-Sub Teleconference we submitted a question asking specifically how we could use the parent device as the predicate when it has a different intended use. During the meeting they confirmed that that is the FDA's recommendation, but they declined to answer this specific question and instead told us to review the accessory guidance (which we took to mean this guidance doc: Medical Device Accessories - Describing Accessories and Classification Pathways (no link b/c it's my first post!)). I have reviewed it several times. I just don't see that this question is covered.

Anyone out there have any thoughts? Thanks in advance.


Starting to get Involved
One option to handle the discrepancy in intended uses would be to frame the submission not as just the accessory, but rather as a submission for a change to the parent device to add the accessory. This is what I believe FDA to be describing in this statement within the guidance you cite:

"Similarly, when the parent device classification regulation identifies only certain accessories, FDA may determine additional accessories to be classified under the regulation through the submission of a 510(k) by the sponsor demonstrating substantial equivalence of the parent device with new accessories to the parent device with the predicate accessories."

The substantial equivalence determination could be made between the parent device w/ and w/o your new accessory, rather than btw the parent device and the accessory directly.

This seems like it would make more sense as an approach if you are also the original manufacturer of the parent device (the needles). Is that the case?


Yeah, I see what you’re saying. That might be an option if we manufactured the parent device, but we do not.


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a change to the parent device to add the accessory.

I don't like 510(k)s and accessories usually make my brain hurt, so I waited for someone to comment substantively before I replied.

Without trying to figure out what FDA is telling you, my reaction was that, if it is declining to tell you something, it is probably declining to stick its neck out. That sometimes means suggesting that you might not need to do something, e.g., submit a 510(k). FDA is not going to tell you this, because, if it does, and you don't do whatever and things go wrong, that could put FDA in front of a congressional committee asking it to explain why it said you didn't have to do it, when obviously (with 20/20 hindsight) that was a bad idea.

It could also mean it is suggesting you might be able to do something easier and quicker than what you are proposing to do. It's not going to tell you this, either, for the same reasons. If a submission that is a change to the parent device would be easier and quicker than the submission you were proposing, then that sounds about right to me.


Hmmm.... not sticking their neck out... might be able to do something quicker and easier.... I have to think about that.

Interesting. So FDA clearly is recommending to use the needles as the "parent predicate device" and pointing us towards the guidance. And one of the accessory guidance's main points is that FDA should, "… classify an accessory under [section 513] based on the risks of the accessory when used as intended and the level of regulatory controls necessary to provide a reasonable assurance of safety and effectiveness of the accessory..." notwithstanding the classification of the parent device. Perhaps they are suggesting that a 510k isn't necessary and are pointing us towards it being Class I or suggesting that submitting an accessory classification request is appropriate.

You might be on to something here! Yeah. Maybe they are suggesting an accessory classification request, in which they might decide it is 510k exempt.

Curiously, we asked the FDA in the pre-sub, basically "do you agree that a 510k using our proposed predicate is appropriate?" Their official response was to refer us to their previous answer where they recommended using the needles as the "parent predicate device." We took this to mean they preferred the needles instead of our proposed predicate, but it could be they are suggesting a different route altogether.

But now, after all the that... the very fact that use the term "predicate" to describe the needles, does suggest a 510k.


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You might be on to something here!

It happens. But, as I said, I don't like 510(k)s or accessories, so not the expert in either. However, as a colleague once said about RA, it's not so much that we are experts in the regulations, but in the regulators. It's a pretty risky claim, to be an "expert" in FDA, but I am at least experienced in listening closely and trying to read between the lines.

It would be good if someone with more 510(k) experience than I have could give you their take on my take.
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