Contains Nonbinding Recommendations
Medical Device Accessories 
Describing Accessories and 
Classification Pathways
Guidance for Industry and
Food and Drug Administration Staff 
Document issued on December 20, 2017. 
Document originally issued on December 30, 2016.
This document supersedes Medical Device Accessories  Describing 
Accessories and Classification Pathway for New Accessory Types, issued 
January 30, 2017.
For questions about this document regarding CDRH-regulated devices, contact the Office of 
Policy at 301-796-5441 or by email at CDRH-Guidance@fda.hhs.gov. 
For questions about this document regarding CBER-regulated devices, contact CBERs Office of 
Communication, Outreach and Development (OCOD) at 1-800-835-4709 or 240-402-8010 or by 
email at ocod@fda.hhs.gov.
U.S. Department of Health and Human Services
Food and Drug Administration
Center for Devices and Radiological Health
Center for Biologics Evaluation and Research
OMB Control No. 0910-0823
Current expiration date available at https://www.reginfo.gov 
See additional PRA statement in Section VII of this guidance Contains Nonbinding Recommendations
Preface
Public Comment
You may submit electronic comments and suggestions at any time for Agency consideration to 
https://www.regulations.gov. Submit written comments to the Division of Dockets Management, 
Food and Drug Administration, 5630 Fishers Lane, Room 1061, (HFA-305), Rockville, MD 
20852.  
Identify all comments with the docket number FDA-2015-D-0025. Comments may not be acted 
upon by the Agency until the document is next revised or updated.
Additional Copies
CDRH
Additional copies are available from the Internet. You may also send an e-mail request to
CDRH-Guidance@fda.hhs.gov to receive a copy of the guidance. Please use the document 
number 1770 to identify the guidance you are requesting.
CBER
Additional copies are available from the Center for Biologics Evaluation and Research (CBER), 
Office of Communication, Outreach, and Development (OCOD), 10903 New Hampshire Ave., 
WO71, Room 3128, Silver Spring, MD 20903, or by calling 1-800-835-4709 or 240-402-8010, 
by email, ocod@fda.hhs.gov, or from the Internet at 
http://www.fda.gov/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guida
nces/default.htm.  Contains Nonbinding Recommendations
Table of Contents
I.  INTRODUCTION ........................................................................................................ 1
II.  BACKGROUND .......................................................................................................... 2
III.  SCOPE .......................................................................................................................... 4
IV.  DEFINITIONS .............................................................................................................. 5
V.  ACCESSORY CLASSIFICATION POLICY .............................................................. 6
A.  Is the article an accessory? ...........................................................................................6
B.  What are the risks of the accessory when used as intended with the parent device(s) 
and what regulatory controls are necessary to provide a reasonable assurance of its safety 
and effectiveness? ..................................................................................................................8
VI.  ACCESSORY CLASSIFICATION PROCESSES....................................................... 8
A.  Accessory Requests ......................................................................................................8
B.  Classification of New Accessory Types through the De Novo Process .....................11
VII.  PAPERWORK REDUCTION ACT OF 1995 ............................................................ 12
APPENDIX 1  REQUEST FOR ACCESSORY DE NOVO CLASSIFICATION .............. 13 Contains Nonbinding Recommendations
Medical Device Accessories 
Describing Accessories and 
Classification Pathways
Guidance for Industry and 
Food and Drug Administration Staff
 
This guidance represents the current thinking of the Food and Drug Administration (FDA 
or Agency) on this topic.  It does not establish any rights for any person and is not binding 
on FDA or the public.  You can use an alternative approach if it satisfies the requirements 
of the applicable statutes and regulations.  To discuss an alternative approach, contact the 
FDA staff or Office responsible for this guidance as listed on the title page. 
I.  Introduction 
The Food and Drug Administration (FDA) developed this document to provide guidance to 
industry and FDA staff about the regulation of accessories to medical devices. This guidance is 
intended to describe FDAs policy concerning the classification of accessories and to discuss the 
application of this policy to devices that are commonly used as accessories to other medical 
devices. In addition, this guidance explains what devices FDA generally considers an 
accessory and describes the processes under Section 513(f)(6) of the Federal Food, Drug, and 
Cosmetic Act (FD&C Act) to allow requests for risk- and regulatory control-based classification 
of accessories.
The FDAs guidance documents, including this guidance, do not establish legally enforceable 
responsibilities. Instead, guidances describe the Agency's current thinking on a topic and should 
be viewed only as recommendations, unless specific regulatory or statutory requirements are 
cited. The use of the word should in Agency guidances means that something is suggested or 
recommended, but not required.
Throughout this guidance document, the terms we, us and our refer to FDA staff from the 
Center for Devices and Radiological Health (CDRH) or the Center for Biologics Evaluation and 
Research (CBER) involved in the review and decision-making aspects of the accessory 
classification process. You and your refer to the submitter of an accessory request, De Novo, 
and/or other related materials.
1 Contains Nonbinding Recommendations
II.  Background
FDA has jurisdiction over accessories because the definition of the term device provided in 
Section 201(h) of the FD&C Act defines device to include, among other products, an 
accessory:
The term device means an instrument, apparatus, implement, machine, contrivance, 
implant, in vitro reagent, or other similar or related article, including any component, 
part, or accessory, which is  
(1) recognized in the official National Formulary, or the United States Pharmacopeia, 
or any supplement to them;
(2) intended for use in the diagnosis of disease or other conditions, or in the cure, 
mitigation, treatment, or prevention of disease, in man or other animals, or
(3) intended to affect the structure or any function of the body of man or other 
animals, and
which does not achieve its primary intended purposes through chemical action within or 
on the body of man or other animals and which is not dependent upon being metabolized 
for the achievement of its primary intended purposes. 
All articles, including accessories, that meet the definition of device above are regulated under 
the FD&C Act.  Accordingly, this guidance describes the types of devices that FDA generally 
considers as accessories and discusses the risk- and regulatory control-based classification 
paradigm for these accessories.  This information is expected to provide a greater level of 
transparency with regards to the classification of accessories and will aid FDA staff and industry 
in assuring that these devices are subject to the appropriate level of regulatory oversight by FDA.
FDA has traditionally determined the classification of device accessory types in one of two 
ways:
 First, by inclusion in the same classification as the parent device, which can be:
o  (1) Through operation of 510(k) Premarket Notification clearance.  In this case, 
the name of the classification regulation identifies only the parent device.  
However, FDA, through the 510(k) submission, may find accessories to the parent 
device to be substantially equivalent to either a predicate parent device with the 
same intended use and technological characteristics, or different technological 
characteristics that do not raise different questions of safety and effectiveness, or 
a predicate accessory that has previously been cleared under the parent devices 
classification regulation with the same intended use and technological 
characteristics, or different technological characteristics that do not raise different 
questions of safety and effectiveness.  These accessories would thus be classified 
within the same classification as the parent device.  Similarly, when the parent 
device classification regulation identifies only certain accessories, FDA may 
determine additional accessories to be classified under the regulation through the 
2 Contains Nonbinding Recommendations
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.
o  (2) Through operation of Premarket Application (PMA) approval.  Accessories 
to an approved Class III device may also be approved in a PMA, in which case 
they would remain in Class III along with the parent device; or
o  (3) By express inclusion in the classification regulation1 or reclassification order2
for the parent device.  In this case, the title of the classification regulation 
specifically cites the name of the parent device type and the corresponding 
accessories.  These classification regulations or orders typically place accessories 
in the same risk- and regulatory control-based classification (e.g., Class I, II, or 
III) as the parent device but sometimes classify accessories into a different risk- 
and regulatory control-based classification.
 Second, by issuance of a unique, separate classification regulation for the accessory.  In 
this case, FDA has determined that a classification regulation for an accessory should be 
separate from that of the corresponding parent device.  This type of classification has 
traditionally been considered for accessory types that may be used with multiple parent 
devices or that have unique standalone functions.  In accordance with this second way, 
FDA may consider issuing a separate classification regulation for a specific category of 
accessories that has been identified as having a different risk profile from that of the 
parent device and thus requires a different level of regulatory controls to provide 
reasonable assurance of safety and effectiveness of the accessories.  
On August 18, 2017, section 513(f) of the FD&C Act was amended by the FDA Reauthorization 
Act of 2017 (Pub. L. 115-52) to state that the Secretary shall ... 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 any other device with which such accessory is 
intended to be used.  Accordingly, the classification of accessory devices, as for non-accessory 
devices, should reflect the risks of the device when used as intended and the level of regulatory 
controls necessary to provide a reasonable assurance of safety and effectiveness.  Classifying an 
accessory in the same class as its parent device is appropriate when the accessory, when used as 
intended with the parent device, meets the criteria for placement in the class of the parent device.  
However, some accessories can have a lower risk profile than that of their parent device and, 
therefore, may warrant being regulated in a lower class.  For example, an accessory to a class III 
parent device may pose lower risk that could be mitigated through general controls or general 
and special controls and thus could be regulated as class I or class II.
1 See section 513(d) of the FD&C Act, 21 U.S.C. 360c(d).
2 Two reclassification processes are described in sections 513(e) and 513(f)(3) of the FD&C Act, 21 U.S.C. 360c(e) 
and (f)(3). Prior to the Food and Drug Administration Safety and Innovation Act of 2012 (FDASIA), FDA 
reclassified devices under section 513(e) of the FD&C Act (21 U.S.C. 360c(e)) through rulemaking; FDASIA 
changed this to an order process.  
3 Contains Nonbinding Recommendations
III.  Scope
This guidance document describes what FDA generally considers an accessory and how the 
FD&C Acts risk- and regulatory control-based framework for classification applies to 
accessories to other medical devices.  In this guidance, we describe considerations for 
determining applicable risk to all articles that meet the definition of an accessory.  This guidance 
is only applicable to articles that meet the definition of a device under section 201(h) of the 
FD&C Act.  
In addition, this guidance describes use of the Accessory Classification processes under section 
513(f)(6) of the FD&C Act, which provides mechanisms for requesting the appropriate 
classification (or reclassification) of 
 an accessory that is included in an application for premarket approval ... under section 
515 or a report under section 510(k) for clearance of such device [intended to be used 
with the accessory] and the Secretary has not classified such accessory distinctly from 
another device,3 and
 an accessory that [has] been granted marketing authorization as part of a submission for 
another device with which the accessory involved is intended to be used, through an 
application for such other device under section 515(c), a report under section 510(k), or a 
request for classification under [513(f)(2)] ...4
While other mechanisms exist to request the appropriate classification of an accessory, this 
guidance focuses on the Accessory Classification process described in section 513(f)(6) of the 
FD&C Act.  For example, for a new accessory type (i.e., an accessory of a type that has not been 
previously classified under the FD&C Act, cleared for marketing under a 510(k) submission, or 
approved in a PMA), the De Novo classification process under section 513(f)(2) may be used to 
obtain classification of such an accessory.5  In addition, manufacturers of accessories within an 
accessory type that has already been classified by regulation or order, or has received PMA 
approval or 510(k) clearance, may seek reclassification6 or exemption from the requirement to 
submit a 510(k) notification7 under applicable sections of the FD&C Act.   
 
FDA intends for the risk- and regulatory control-based classification paradigm discussed in this 
guidance to apply to all software products that meet the definition of an accessory, including 
those that may also meet the definition of Software as a Medical Device (SaMD).
As part of the FDAs efforts for international convergence, the International Medical Device 
Regulators Forum (IMDRF) adopted the definition of SaMD as software intended to be used for 
3 See section 513(f)(6)(C)(i) of the FD&C Act.
4 See section 513(f)(6)(D) of the FD&C Act.
5 See section 513(f)(6)(E) of the FD&C Act.
6 See sections 513(e) and 513(f)(3) of the FD&C Act. 
7 See section 510(m) of the FD&C Act.  
4 Contains Nonbinding Recommendations
one or more medical purposes that perform these purposes without being part of a hardware 
medical device. 8  
SaMD that meets the definition of a device under the FD&C Act is regulated by FDA.  However, 
SaMD that meets this device definition and uses data from a medical device does not 
automatically become an accessory for purposes of this guidance.  For example, a stand-alone 
software program that is intended to analyze radiological images or analyzes specific data 
parameters generated by a device (e.g., blood pressure data or heart rate data) is considered a 
SaMD but would not be considered to support, supplement, and/or augment the performance of 
the device that generated data, and therefore, would not be an accessory. 
In some cases, software that meets the definition of SaMD may be used in combination (e.g., as a 
module) with other devices.  In these cases, the SaMD may also be considered an accessory if it 
supports, supplements, and/or augments the performance of one or more parent devices, as 
described in Section IV below.  
Regardless of whether a SaMD uses data from other devices or is used in combination with other 
devices, the FDA intends to apply the same risk- and regulatory control-based classification 
paradigm discussed in this guidance to all software products that meet the definition of SaMD 
and also meet the definition of an accessory.
IV.  Definitions
Accessory:  A finished device that is intended to support, supplement, and/or augment the 
performance of one or more parent devices. 
 
Component (21 CFR 820.3(c)):  [A]ny raw material, substance, piece, part, software, 
firmware, labeling, or assembly which is intended to be included as part of the finished, 
packaged, and labeled device. 
 
Finished Device (21 CFR 820.3(l)): [A]ny device or accessory to any device that is suitable for 
use or capable of functioning, whether or not it is packaged, labeled, or sterilized.9
Parent Device:  A finished device whose performance is supported, supplemented, and/or 
augmented by one or more accessories.
8 See IMDRF SaMD WG/N10 Final:  Software as a Medical Device: Key Definitions 
(http://www.imdrf.org/docs/imdrf/final/technical/imdrf-tech-131209-samd-key-definitions-140901.pdf)
9 Note that the preamble to the Quality System Final Rule (61 FR 52609, October 7, 1996) states To better clarify 
its intent, FDA has amended the definition to add that all devices that are capable of functioning, including those 
devices that could be used even though they are not yet in their final form, are finished devices. For example, 
devices that have been manufactured or assembled, and need only to be sterilized, polished, inspected and tested, or 
packaged or labeled by a purchaser/manufacturer are clearly not components, but are now in a condition in which 
they could be used, therefore meeting the definition of finished device.
5 Contains Nonbinding Recommendations
V.   Accessory Classification Policy
The policy governing the classification of accessories is subject to the same risk- and regulatory 
control-based scheme under the FD&C Act that FDA uses to classify all medical devices.  The 
risks of an accessory are the risks that it presents when used with the corresponding parent 
device as intended.  In order to classify an accessory, FDA addresses the following two 
questions: 
1.  Is the article an accessory?
2.  What is the risk of the accessory when used as intended with the parent device(s) and 
what regulatory controls are necessary to provide a reasonable assurance of its safety and 
effectiveness?
The answers to these two questions inform the risk- and regulatory control-based classification 
of a potential accessory pursuant to the criteria at section 513(a)(1) of the FD&C Act.  Individual 
accessories may either be classified pursuant to the same regulation as a corresponding parent 
device, when appropriate, or be regulated independently.  The following subsections provide 
further details and considerations regarding the risk- and regulatory control-based classification 
for accessories.
A.  Is the article an accessory?
The accessory classification process begins with the analysis of whether the article under 
consideration is an accessory as described in this guidance document.  We consider an 
accessory as an article that:
1.  Is intended for use with one or more parent devices. 
 
FDA expects that whether an article is intended for use with a parent device 
will generally be determined by the labeling and promotional materials for the 
potential accessory device (rather than by the labeling and promotional 
materials for the parent device).  If labeling, promotional materials, or other 
evidence of intended use demonstrates that an article is intended for use with a 
parent device (either a particular brand or a device type), and it supports, 
supplements, and/or augments that device, FDA generally considers the article 
to be an accessory and, thus, a device as defined in section 201(h) of the 
FD&C Act. This includes those articles labeled as being optional.
It is important to note that FDA does not generally consider articles that do 
not meet the definition of an accessory as accessories simply because they 
may be used in conjunction with a device.  For example, FDA would 
generally not consider 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 as 
accessories unless they are specifically intended for use with such medical 
devices.  
6 Contains Nonbinding Recommendations
2.  Is intended to support, supplement, and/or augment the 
performance of one or more parent devices.   
 
A device supports the performance of a parent device by enabling or 
facilitating that device to perform according to its intended use.  For example, 
a tunneling tool for a neurostimulation device that is intended to create a 
conduit for the leads between the target location to the neurostimulator 
supports the neurostimulator by facilitating it to provide stimulation to the 
target neural tissue.  In this case, the accessory is necessary to enable the 
parent device to meet its intended use.  An infusion pump stand also supports 
the intended use of a parent device (an infusion pump) by holding medications 
or liquids and other infusion accessories firmly, at an appropriate height, and 
in convenient reach of the patient or caregiver.  In this case, the parent device 
can perform its intended use without the accessory, but the accessory 
nonetheless supports the performance of the device.   
 
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.  For example, a pulse oximeter allows a 
multi-parameter monitor to display oxygen saturation but does not change its 
intended use, which is to record and display multiple physiological 
parameters.  Similarly, a new balloon catheter used to insert an already 
approved transcatheter heart valve into a smaller diseased artery supplements 
the parent devices intended use.  The balloon catheter supplements the 
intended use of the transcatheter heart valve by expanding the population of 
patients who can receive the parent device to those with smaller diameter 
arteries, such as women.   
 
A device augments the performance of a parent device by enabling the device 
to perform its intended use more safely or effectively.  Augments includes 
improving the performance of a parent device by enabling it to perform more 
quickly or improving usability or convenience for the device user.  For 
example, a guidewire augments the performance of a bone-cutting instrument 
by increasing precision of the parent device and reducing the risk to the 
patient.  Similarly, a software program that adds color or contrast filters to 
enhance raw images generated by an imaging device augments the 
performance of a parent device by enabling it to perform more effectively. 
 
In practice, the distinctions among devices that support, supplement, or 
augment parent devices are subtle and many devices that meet the definition 
of an accessory may do more than one of these things.  Thus, if the device is 
intended to support, supplement, and/or augment the performance of one or 
more parent devices, we intend to consider the device to be an accessory 
whether it is required or optional..   
 
Some products that are not specifically intended for use, but nevertheless may 
7 Contains Nonbinding Recommendations
be used, with a medical device and which do not meet the definition of an 
accessory may not warrant independent classification if they are not devices 
under Section 201(h) of the FD&C Act.  As an example, non-device-specific 
off-the-shelf replacement parts (e.g., batteries, USB cables, computer mouse, 
etc.) may be used with a medical device, but FDA does not intend to consider 
these products to be accessories or medical devices.  
B.  What are the risks of the accessory when used as intended 
with the parent device(s) and what regulatory controls 
are necessary to provide a reasonable assurance of its 
safety and effectiveness? 
Under the policy described in this guidance, FDA intends to determine the risk of 
accessories and the regulatory controls necessary to provide a reasonable assurance of 
their safety and effectiveness according to their intended use in the same manner that is 
used to determine such for devices that are not accessories.  Because accessories are 
intended to be used with and to support, supplement, and/or augment one or more parent 
devices, FDA intends to determine the risks of accessories when used, as intended, with 
the parent device type.   
 
Determining the risks of accessories according to their use with parent devices does not 
mean that all risks of a parent device are imputed to the accessory; the risk profile of an 
accessory can differ significantly from that of the parent device, warranting differences in 
regulatory classification.  In determining the classification of an accessory, FDA intends 
to evaluate the risks imposed by the accessorys impact on the parent device and any 
unique risks of the accessory independent of its parent device.  As with the classification 
of any other device, the types of regulatory controls necessary to control these risks of the 
use of the accessory device with the parent device will determine the regulatory class for 
accessories.
VI.  Accessory Classification Processes
A.  Accessory Requests
The appropriate classification or reclassification of a legally-marketed accessory or a new 
accessory type can be requested under section 513(f)(6) of the FD&C Act through the 
Accessory Request types described below.  Note that FDA intends to  track Accessory 
Requests as Q-Submissions.
For devices regulated by CDRH, Accessory Requests should be submitted to:
U.S. Food and Drug Administration
Center for Devices and Radiological Health 
Document Control Center  WO66-G609
8 Contains Nonbinding Recommendations
10903 New Hampshire Ave 
Silver Spring, Maryland 20993-0002
For devices regulated by CBER, Accessory Requests should be submitted to:
U.S. Food and Drug Administration
Center for Biologics Evaluation and Research
Document Control Center 
10903 New Hampshire Ave.
WO71-G112
Silver Spring, Maryland 20993-0002
1.  New Accessory Type
In accordance with section 513(f)(6)(C) of the FD&C Act, you may submit an 
Accessory Request for appropriate classification of an accessory that is included 
in a PMA, PMA supplement, or 510(k), if the accessory has not been classified 
distinctly from another device.  This New Accessory Request is appropriate for an 
accessory of a type that has not been previously classified under the FD&C Act, 
cleared for marketing under a 510(k) submission, or approved in a PMA.  This 
request should be submitted together with the parent device submission and 
include a cover letter that clearly identifies that the submission includes a New 
Accessory Request.  The proposed classification of the accessory (i.e., class I or 
class II) should also be clearly identified in the cover letter and/or the request.  In 
addition, the request should provide the necessary information, based on Least 
Burdensome principles, to establish the risk profile of the accessory when used as 
intended with the parent device as described in section V.B. above.  Note that 
requests for classification of an accessory in class II must include an initial draft 
proposal for special controls, if special controls would be required pursuant to 
subsection 513(a)(1)(B) of the FD&C Act.10  
Since a Pre-Submission is appropriate when FDAs feedback on specific 
questions is necessary to guide product development and/or application 
preparation, we recommend that you submit a Pre-Submission to request feedback 
on a proposed Accessory Request.  For more information, see Requests for 
Feedback on Medical Device Submissions: The Pre-Submission Program and 
Meetings with Food and Drug Administration Staff - Guidance for Industry and 
Food and Drug Administration Staff 
(https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceD
ocuments/UCM311176.pdf).
FDA must grant or deny the New Accessory Request concurrently with the 
decision on the premarket submission with which the request was submitted.11  If 
the New Accessory Request is granted, we will issue you an order establishing a 
new classification for such accessory for the specified intended use or uses of 
10 See section 513(f)(6)(C)(i)(III) of the FD&C Act.
11 See section 513(f)(6)(C)(ii) of the FD&C Act.
9 Contains Nonbinding Recommendations
such accessory and for any accessory with the same intended use or uses as such 
accessory.  Effective on the date of the granting order, the requester may 
immediately begin marketing the device subject to the general controls and any 
identified special controls.  If the New Accessory Request is denied but the 
premarket submission with which it was submitted is cleared or approved, the 
accessory may be legally marketed but will be considered to be in the same 
classification as the parent device. 
2.  Existing Accessory Type
In accordance with section 513(f)(6)(D) of the FD&C Act, you may submit an 
Accessory Request for appropriate classification of an accessory that has been 
granted marketing authorization as part of a submission for another device with 
which the accessory involved is intended to be used, through a premarket 
submission or a De Novo request for such other device (referred to as an 
Existing Accessory Type).  The Accessory Request should include a cover 
letter that clearly identifies that the submission is an Existing Accessory 
Request.  The proposed classification of the accessory (i.e., class I or class II), as 
well as the current classification, should also be clearly identified in the cover 
letter and/or the request.  An Existing Accessory Request should include the 
necessary information, based on Least Burdensome principles, to establish the 
risk profile of the accessory when used as intended with the identified parent 
device as described in section V.B. above.  Note that requests for classification of 
an accessory in class II must include an initial draft proposal for special controls, 
if special controls would be required pursuant to subsection 513(a)(1)(B) of the 
FD&C Act.12  Prior to the submission of an Existing Accessory Request, FDA 
will provide an opportunity for a meeting to discuss the appropriate classification 
of the accessory, upon request. 13
Since a Pre-Submission is appropriate when FDAs feedback on specific 
questions is necessary to guide product development and/or application 
preparation, we recommend that you submit a Pre-Submission to request feedback 
on a proposed Accessory Request.  For more information, see Requests for 
Feedback on Medical Device Submissions: The Pre-Submission Program and 
Meetings with Food and Drug Administration Staff - Guidance for Industry and 
Food and Drug Administration Staff 
(https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceD
ocuments/UCM311176 
FDA must grant or deny the Accessory Request for an Existing Accessory Type 
within 85 days of receiving the request.14  If the request is granted, we will issue 
you a written order granting the Accessory Request and identifying the 
classification of the device (either class I or class II).  We will then publish a final 
12 See section 513(f)(6)(D)(ii) of the FD&C Act.
13 See section 513(f)(6)(D)(ii) of the FD&C Act.
14 See section 513(f)(6)(D)(iii) of the FD&C Act.
10 Contains Nonbinding Recommendations
order in the Federal Register providing public notice of the decision, which will 
result in codification of the devices identification, classification, and applicable 
requirements in Title 21 of the Code of Federal Regulations (device 
classifications are at parts 862  892).  If FDA does not agree with the 
recommendation for classification submitted in the request, we will provide a 
written response that includes a detailed description and justification for the 
denial of the request. 
B.  Classification of New Accessory Types through the De 
Novo Process
In addition to the Accessory Requests under Section 513(f)(6), you can utilize the De 
Novo classification process in Section 513(f)(2) of the FD&C Act to request risk- and 
regulatory control-based classifications of new accessory types.  In order to be considered 
a new accessory type, the accessory under consideration should not be classified by an 
existing classification regulation and should not be the subject of any approved PMAs or 
cleared 510(k)s for that accessory type.  This De Novo classification process provides a 
pathway to class I or class II classification for accessories with low to moderate risk for 
which general controls or general and special controls provide a reasonable assurance of 
safety and effectiveness, but for which there are no legally marketed predicate devices.  
For additional information regarding the De Novo classification process, please see De 
Novo Classification Process (Evaluation of Automatic Class III Designation); Guidance 
for Industry and Food and Drug Administration Staff 
(https://www.fda.gov/ucm/groups/fdagov-public/@fdagov-meddev-
gen/documents/document/ucm080197.pdf).  Please also refer to Appendix 1 (below) for 
the information FDA recommends be submitted in a De Novo request for a new 
accessory type.
FDA must make a classification determination for the device that is the subject of the De 
Novo request by written order within 120 days of the request.15  If the submitter 
demonstrates that the criteria in section 513(a)(1)(A) or (B) of the FD&C Act are met 
(i.e., accessories for which general controls or general and special controls provide a 
reasonable assurance of safety and effectiveness), FDA will grant the De Novo request, 
which classifies the new accessory (and accessory type) in class I or class II.  The 
accessory may then be marketed immediately and serve as a predicate device for future 
510(k) premarket notifications, if applicable.  FDA will publish a notice in the Federal 
Register announcing the classification and the regulatory controls necessary to provide 
reasonable assurance of safety and effectiveness of the accessory.  If the request to 
undertake De Novo classification is declined,16 the accessory remains in class III under 
15 See section 513(f)(2)(A)(iii) of the FD&C Act.
16 A request to undertake the De Novo classification could be declined for reasons including if the performance data 
provided in the De Novo request do not support that general controls or general and special controls can 
appropriately mitigate identified risks to health for the device to provide a reasonable assurance of safety and 
effectiveness.  
11 Contains Nonbinding Recommendations
section 513(f)(1) of the FD&C Act and may not be marketed until a PMA is submitted by 
the sponsor and approved by FDA.
VII. Paperwork Reduction Act of 1995
This guidance contains information collection provisions that are subject to review by the Office 
of Management and Budget (OMB) under the Paperwork Reduction Act of 1995 (44 U.S.C. 
3501-3520).
The time required to complete this information collection is estimated to average 180 hours per 
response, including the time to review instructions, search existing data sources, gather the data 
needed, and complete and review the information collection.  Send comments regarding this 
burden estimate to:
FDA PRA Staff,
Office of Operations,
Food and Drug Administration,
PRAStaff@fda.hhs.gov 
An agency may not conduct or sponsor, and a person is not required to respond to, a 
collection of information unless it displays a currently valid OMB control number.  
The OMB control number for this information collection is 0910-0823 (To find the 
current expiration date, search for this OMB control number available at 
https://www.reginfo.gov).
12 Contains Nonbinding Recommendations
Appendix 1  Request for Accessory De Novo Classification
Manufacturers or other interested parties may seek a decision by the FDA on the appropriate 
risk- and regulatory control-based classification of a new type of accessory by filing a De Novo 
request (hereafter a De Novo) under section 513(f)(2) of the FD&C Act.  This process is also 
known as the De Novo classification process.17
In order to streamline the submission and evaluation of the accessory De Novo so that only 
information necessary to assess accessory safety and effectiveness is submitted and reviewed, we 
recommend that the following information be provided:
 Clear identification as a De Novo request for a new accessory device type;
 Device Information and Summary: 
 A description of the relevant parent device(s); 
 A description of the ability for the accessory to be compatible with a specific 
parent device, multiple parent devices, or a class of devices;
 A description of the technical characteristics of the accessory, which ensure 
compatibility with a specific parent device, multiple parent devices, or a class 
of devices; 
 A description of how the accessory supports, supplements and/or augments 
the performance of the parent device.
 Identification of parent product(s) to which the accessory is compatible, including 
model number, connector type, etc.;
 Classification summary and recommendation:
 The classification summary should include a rationale for why the accessory 
device does not fit within any identified classification for the parent device(s);
 An identification of the risks to health presented by the accessory device and 
proposed mitigation measures;
 Proposed controls: 
 For proposed class II devices, a list of general and special controls that 
sufficiently mitigate the risks to health, including compatibility of the 
accessory device with the parent device and a description of how the proposed 
special controls will provide a reasonable assurance of safety and 
effectiveness for the accessory device 
 For proposed class I devices, an identification of how the application of 
general controls only would sufficiently mitigate the risks to health and would 
provide a reasonable assurance of safety and effectiveness of the accessory 
device;
 Summary of the performance data supporting the De Novo: 
 Reference to all reasonably known relevant data and information, including 
new information, about the accessory device and/or the accessory in 
17 See De Novo Classification Process (Evaluation of Automatic Class III Designation); Guidance for Industry and 
Food and Drug Administration Staff (https://www.fda.gov/ucm/groups/fdagov-public/@fdagov-meddev-
gen/documents/document/ucm080197.pdf). 
13 Contains Nonbinding Recommendations
combination with the parent device(s), whether favorable or unfavorable to 
the proposed classification; and
 Labeling for the accessory with adequate instructions for use with the parent 
device(s):
 Include labeling instructions to address compatibility of the new accessory 
device and the parent device(s), including any relevant performance data to 
support compatibility; and
 Include relevant technical characteristics of the accessory.
In preparing a De Novo request for an accessory of a new type, we suggest you review 
publicly posted information, including decision summary documents, for recently granted 
CDRH De Novo requests available on our website at 
http://www.fda.gov/AboutFDA/CentersOffices/OfficeofMedicalProductsandTobacco/CDRH/
CDRHTransparency/ucm232269.htm.
In an effort to further streamline and facilitate FDAs review of your accessory De Novo 
classification request, we recommend that you provide a draft executive summary document 
with the following information:
 Administrative information, 
 Proposed identification language for a new classification regulation or order;
 Summary of the accessory device, including a detailed description of the 
accessory, including any necessary technical characteristics and compatibility 
information with the parent device(s);
 Summary of the performance data to support the proposed classification 
recommendation;
 Risk and Mitigation Information:  for class I accessory devices, an explanation 
of how general controls adequately mitigate any risks to health; for class II 
accessory devices, listing of the risks and mitigation measures, including the 
special controls necessary to mitigate the risks to health; and
 Benefit/Risk Considerations.18
18 For information on benefit-risk determinations and factors considered, please see FDA guidance titled Guidance 
for Industry and Food and Drug Administration Staff - Factors to Consider When Making Benefit-Risk 
Determinations in Medical Device Premarket Approval and De Novo Classifications, available at 
https://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM517504
.pdf.
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