January 30, 2015

FDA Issues New Guidance, Classification Pathway on Medical Device Accessories

Arnold & Porter Advisory

On January 20, 2015, the Food and Drug Administration's (FDA) Center for Devices and Radiological Health (CDRH) issued a draft guidance for industry entitled, "Medical Device Accessories: Defining Accessories and Classification Pathway for New Accessory Types."1  The draft guidance outlines CDRH's proposal to apply a risk-based approach for determining the classification of accessory devices that would allow certain lower risk accessories to have a different and lower risk classification than their parent devices.  The guidance also provides a pathway for marketing certain lower risk accessories for which there is no legally marketed predicate device.  Stakeholders may submit comments on the draft guidance until April 20, 2015.2


Under the Federal Food, Drug, and Cosmetic Act (FDCA), medical devices are classified into one of three categories (Class I, II, or III)  based on the degree of regulation required to assure that they are safe and effective for their intended uses.  The statutory definition of "device" includes "accessories" and "components."  FDA's device Quality System Regulation (QSR) defines "components" as items that are included in a finished device.3  Most components are not directly subject to medical device requirements such as establishment registration and device listing or QSR.  Accessories, however, are not specifically defined in the regulation, but they are included in the definition of "finished device" and subject to medical device requirements.4  Consequently, FDA developed a longstanding practice of classifying and regulating accessories under the same regulation as the devices with which they are intended to work. 

For novel or unique accessories that did not fit within any of the approximately 1,700 generic device-types described in FDA's device classification regulations, FDA established a de novo review process, in which a manufacturer could submit data to establish the safety and effectiveness of the accessory outside of the lengthy and data-intensive premarket approval (PMA) process for higher risk Class III devices.  The de novo process created an abbreviated pathway for manufacturers to market accessories that were ineligible for review under the traditional premarket clearance (510(k)) process because there were no predicate devices to which they could be compared.

Although the de novo process created a much-needed path to market for many novel and life-saving devices, the absence of a risk-based regulatory approach for most other accessories sometimes resulted in inconsistent regulatory outcomes for similar products and confusion in the marketplace.  CDRH's guidance attempts to address complaints and confusion regarding FDA's one-size-fits-all approach to regulating accessories by defining the term "accessory," announcing a two-pronged test to determine whether a product is an accessory, and proposing a risk-based regulatory framework for classifying and regulating accessories.

The guidance defines a medical device "accessory" as "a device that is intended to support, supplement, and/or augment the performance of one or more parent devices."  A "parent device" is "a finished device whose performance is supported, supplemented, and/or augmented by one or more accessories."  CDRH then describes a two-pronged test for determining whether a device is an accessory.  According to the guidance, CDRH will evaluate whether the article is intended: (1) for use with one or more parent devices; and (2) to support, supplement, and/or augment the performance of one or more parent devices.

According to CDRH, the determination of a product's intended use begins with its labeling and promotional materials.  This approach is consistent with FDA's long-standing practice of relying on product claims and labeling to establish the regulatory status of medical devices and other products.  The guidance clarifies, however, that CDRH intends to focus on the labeling and promotional materials for the accessory device itself, rather than the parent device as it has in the past.  

The guidance further clarifies that devices that do not meet the definition of "accessory" do not become accessories "simply because they may be used in conjunction with a device."5  Rather, it should be clear from the product's labeling and other evidence of use that it is intended to support, supplement or augment a particular device or one or more device-types.  CDRH noted, for example, that "a mobile phone that is used as a general platform for applications that include mobile medical applications that are medical devices, or an off-the-shelf computer monitor used to display medical data would not be considered accessories unless they are intended for use with such devices."  This is an important clarification, which may avoid potential confusion regarding the regulatory status of certain consumer products or general purpose communication platforms and software that can be configured to work with a medical device, but may not be marketed or intended for this purpose.

The guidance also defines the terms "support," "supplement," and "augment," and describes how these concepts fit within the new risk-based regulatory framework for accessories.  According to CDRH, a device "supports" the performance of a parent device if it enables or facilitates the device to perform according to its intended use (e.g., a rechargeable battery intended to operate when paired with an automated external defibrillator (AED)).  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" (e.g., a new balloon catheter used to insert an already approved transcatheter heart valve into a smaller diseased artery supplements the parent device's intended use).6  Lastly, a device "augments" the performance of a parent device by enabling the device to perform its intended use more safely or effectively, or "improving the performance of a parent device by enabling it to perform more quickly or improving usability or convenience for the device user" (e.g., a guidewire augments the performance of a bone-cutting instrument by increasing precision of the parent device and reducing the risk to the patient).7

Risk-Based Classification

CDRH's guidance explains that the classification of accessory devices should reflect the risks of the device when used as intended with the corresponding parent device.  This approach aligns CDRH's new regulatory policy for accessories with the established risk-based framework that exists for all other medical devices.  For example, an accessory to a Class III parent device may pose lower risks that could be mitigated through general controls or general and special controls and thus could be regulated as Class I or Class II.  CDRH explained that it will not impute all risks of a parent device to an accessory, but rather, "will evaluate the risks imposed by the accessory's impact on the parent device and any unique risks of the accessory independent of its parent device."  The types of regulatory controls necessary to control the risks will determine the regulatory class for accessories.

Accessory Classification through the De Novo Process

CDRH's guidance encourages manufacturers to utilize the de novo classification process under Section 513(f)(2) of the FDCA to request a risk-based classification of accessories that have not been previously classified or approved in an application for a PMA.  Manufacturers may utilize this pathway to request a Class I or Class II designation for an accessory.  Class III accessories must be approved through the PMA process.  It is important to note that the de novo process cannot be used to reclassify an accessory that was previously classified by regulation or order.8 Requests for reclassification or an exemption from premarket clearance requirements are governed by different statutory provisions.9

FDA must make a classification determination by written order within 120 days of the request.10  Appendix 1 of the guidance contains CDRH's recommendations regarding the content and data manufacturers should include in a de novo request for a new type of accessory.  It appears that CDRH is already applying these risk-based classification principles and the de novo preview process to recently marketed devices.  Within one week of releasing its guidance, CDRH cleared the Dexcom Share Direct Secondary Displays System, which is a mobile medical application (MMA) that allows people with diabetes to automatically and securely share data from a continuous glucose monitor (CGM) with third-parties (e.g., caregivers) in real-time using a mobile device such as a smart phone.11  FDA classified the Dexcom Share Direct Secondary Displays system through the de novo process as a Class II, 510(k)-exempt device.  FDA classified the MMA as an accessory to the Dexcom CGM System, which is a Class III device.  Although FDA's press release does not describe the factors or criteria it applied in assigning a different classification to the MMA, the agency noted that devices like the Dexcom Share were previously available through open source efforts.  According to FDA, however, many of the open source devices were not in compliance with regulatory requirements.  Prior to this guidance, FDA's decision to assign a different classification to the MMA would have been a departure from its longstanding policy for accessories.


While the accessory guidance and CDRH's recent classification of Dexcom's CGM system accessories offer additional insight into FDA's willingness to consider down classifying accessories that present a lower risk profile than that of the parent device, the policy nevertheless lacks specific details regarding several issues including, but not limited to:

  • Validation requirements for claims associated with an accessory;
  • How to determine whether an accessory is regulated as part of a system;
  • Whether general purpose hardware and software sold with preloaded medical software of a parent device meets FDA's definition of an accessory;
  • How CDRH intends to balance and weigh an accessory's risks and potential impacts in different therapeutic settings or device categories;
  • Which factors CDRH will consider in determining the extent to which an accessory's risk profile when it is used as a stand-a-lone product should impact the risk assessment when it is used with a parent device;  and
  • The regulatory and safety impact of interoperability labeling or promotional claims for devices that may be used in conjunction with another device, but do not fit within the accessory definition.

Finally, given CDRH's focus on accessory labeling and promotional materials, manufacturers will need to play close attention to both express and implied claims regarding their accessories, including those made by the manufacturers of the parent device, third party vendors and downstream retailers.

  1. Available here.

  2. 80 Fed. Reg. 2710 (Jan. 20, 2015), available here.

  3. See 21 CFR § 820.3(c).

  4. See 21 CFR § 820.3(l) (defining "finished device" to include "any device or accessory to any device that is suitable for use or capable of functioning, whether or not it is packaged, labeled, or sterilized.").

  5. Guidance at 5.

  6. Id. at 5.

  7. Id. at 6. Similarly, tools for the placement of an implantable nerve stimulator according to its intended use augment the performance of the stimulator by facilitating successful placement.

  8. See Section 513(e) and Section 513(f)(3) of the FDCA.

  9. See Section 510(m) of the FDCA.

  10. See Section 513(f)(2)(A)(iii) of the FDCA.

  11. Available here.


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