FDA Defines Medical Device Accessory, Proposes New Means for Classification

By Jennifer D. Newberger –

The question of what constitutes an accessory has never been well answered.  In a December 1996 guidance document, Medical Device Quality Systems Manual: A Small Entity Compliance Guide, FDA said that accessory devices are devices “packaged, labeled, and distributed separately to a hospital, physician, etc., for health-related purposes.”  Apart from this, no definition of this statutory term was ever provided.   Despite the lack of a definition for accessories, FDA historically classified accessories either by classifying the accessory in the same class as the parent device, or by issuing a separate classification regulation. 

On January 20, 2015, FDA issued a draft guidance document putting forth a definition for accessory, and proposing a new way of classifying accessories.  The draft guidance defines an accessory as a “device that is intended to support, supplement, and/or augment the performance of one or more parent devices.”  This definition is further parsed as follows:

• “A device supports the performance of a parent device by enabling or facilitating that device to perform according to its intended use.”
• “A device supplements the performance of a parent device if it adds a new function or a new way of using the parent device, without changing the intended use of the parent device.”
• “A device augments the performance of a parent device by enabling the device to perform its intended use more safely or effectively.”

These distinctions are likely to be difficult to apply in practice.  To provide more clarity, FDA gave some examples, some of which seem questionable.  For example, FDA states that a rechargeable battery intended to operate when paired with an automated external defibrillator (AED) is an accessory to the AED because it is intended to support the AED by enabling it to defibrillate.  It would not seem that a battery that is required for the operation and function of the parent device would be considered an accessory, but rather part of the parent device itself.

As an example of an accessory that “supplements” the parent, FDA cited a pulse oximeter that allows a multi-parameter monitor to display oxygen saturation but does not change its intended use:  to record and display multiple physiological parameters.  While multi-parameter monitors are cleared to display specific parameters, including oxygen saturation, they are rarely cleared for use with specific devices.  Additionally, a pulse oximeter is a finished device with its own regulatory classification that requires 510(k) clearance.  It is therefore not evident that a pulse oximeter would appropriately be considered an “accessory” to a multi-parameter monitor.  In light of the examples provided, the definition of an accessory would seem to include a larger number of devices than previously believed to be accessories, and could presumably include any device that, for any purpose, is intended to be used with another device.

In addition to questionable examples of accessories, the draft guidance proposes that manufacturers consider submitting de novo classification petitions for device accessories.  The intent behind the proposal may be well-founded:  some accessories may have a lower risk profile than their parent, and therefore may warrant being regulated in a lower class.  The application, however, seems flawed.  First, as noted above with respect to the AED battery, some “accessories” are key to the functionality of the device, and it is debatable whether FDA would clear or approve a submission that did not include a key part of the product. Second, the utility of the de novo process for accessories would be limited because it would apply only to accessories “of a new type.”  Finally, it is not clear in what circumstances use of de novo for an accessory would be appropriate or practical.  FDA proposes this approach in very high-level, theoretical terms, but provides no examples of when de novo classification for an accessory may actually be suitable.

While it is welcome to, at long last, have FDA provide a definition of an accessory, the examples provided do not seem to fit the traditional understanding of an accessory.  Furthermore, the proposal to utilize the de novo pathway is likely to be beneficial only in limited circumstances that are not entirely evident.  Thus, while the draft guidance does provide a definition, it will not likely alter the way in which accessories are cleared.