Contains Nonbinding Recommendations 
 
 
FDA Categorization of Investigational 
Device Exemption (IDE) Devices to 
Assist the Centers for Medicare and 
Medicaid Services (CMS) with 
Coverage Decisions 
 ____________________________________________________________________________ 
Guidance for Sponsors, Clinical 
Investigators, Industry, Institutional 
Review Boards, and Food and Drug 
Administration Staff
 
 
Document issued on December 5, 2017. 
 
The draft of this document was issued on June 1, 2016. 
 
This document supersedes IDE Guidance Memorandum #95-2 
Implementation of the FDA/HCFA Interagency Agreement Regarding 
Reimbursement Categorization of Investigational Devices issued on 
September 15, 1995. 
 
For questions about this document as applied to devices regulated by the Center for Devices and 
Radiological Health (CDRH), contact CDRHClinicalEvidence@fda.hhs.gov.  
 
For questions regarding this document as applied to devices regulated by the Center for Biologics 
Evaluation and Research (CBER), contact the Office of Communication, Outreach and 
Development in CBER at 1-800-835-4709 or 240-402-8010 or 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 
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  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 Dockets Management Staff, Food 
and Drug Administration, 5630 Fishers Lane, Room 1061, (HFA-305), Rockville, MD 20852. 
Identify all comments with the docket number FDA-2016-D-1159. 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 
1500074 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., 
Bldg. 71, Room 3128, Silver Spring, MD 20993-0002, or by calling 1-800-835-4709 or 240-402-
8010, by email, ocod@fda.hhs.gov, or from the Internet at 
https://www.fda.gov/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guid
ances/default.htm. 
 
 
 
 
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  Contains Nonbinding Recommendations 
 
 
Table of Contents 
 
 
I.  Introduction ............................................................................................................................. 4 
II.  Background ............................................................................................................................. 5 
III.  FDA Interpretation of Medicare Coverage Categories A and B ............................................. 8 
IV.  Considerations When Changing from Category A to B .......................................................... 9 
V.  Examples ............................................................................................................................... 11 
VI.  Conclusions ........................................................................................................................... 13 
Appendix A: Category Decision Flowchart .................................................................................. 14 
 
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  Contains Nonbinding Recommendations 
 
 
FDA Categorization of Investigational 
Device Exemption (IDE) Devices to 
Assist the Centers for Medicare and 
Medicaid Services (CMS) with 
Coverage Decisions 
 
 
Guidance for Sponsors, Clinical 
Investigators, Industry, Institutional 
Review Boards, 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 
 
This guidance modifies the Food and Drug Administrations (FDAs or the Agencys) current 
policy on categorizing investigational device exemption (IDE) devices, which assists the Centers 
for Medicare & Medicaid Services (CMS) in determining whether or not an IDE device should 
be covered (reimbursed) by CMS.   
 
On December 2, 2015, FDAs Center for Devices and Radiological Health (CDRH) and CMSs 
Coverage and Analysis Group (CAG) executed a Memorandum of Understanding (MOU)1 to 
                                                           
1 The MOU can be accessed at 
https://www.fda.gov/AboutFDA/PartnershipsCollaborations/MemorandaofUnderstandingMOUs/DomesticMOUs/uc
m477091.htm. 
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  Contains Nonbinding Recommendations 
 
 
streamline and facilitate the efficient categorization of investigational medical devices in order to 
support CMSs ability to make Medicare coverage (reimbursement) determinations for those 
investigational devices under 42 CFR 405 Subpart B.  The MOU noted the need for FDA and 
CMS to revise their shared understanding regarding categorization.  This guidance document is 
intended to implement the MOU by further explaining the framework that FDA (both CDRH and 
the Center for Biologics Evaluation and Research (CBER)) intends to follow for such decisions.  
This guidance applies to all devices reviewed by CDRH and CBER.  The MOU took effect June 
2, 2016 (six months following signature by both FDA and CMS, as stated in the MOU).  The 
framework in this guidance represents the Agencys current thinking on categorization. 
II.  Background 
 
1995 Final Rule and FDA-HCFA Interagency Agreement 
 
In September 1995, the Health Care Financing Administration (now known as CMS) published a 
final rule and entered into an Interagency Agreement (IA) with FDA regarding reimbursement 
categorization of investigational devices. 60 Federal Register (FR) 48417 (September 19, 1995).  
The rule established that certain devices with an IDE approved by FDA (and certain services 
related to those devices) may be covered under Medicare, and set forth the process by which 
FDA would assist CMS in identifying such devices.  FDA would assign a device with an FDA-
approved IDE to one of two categories: Experimental/Investigational (Category A) devices or 
Non-experimental/Investigational (Category B) devices based on the level of risk the device 
presented to patients.  The IA set forth criteria, agreed upon by CMS and FDA, that FDA would 
use to categorize devices. The categorization would then be used by CMS as part of its 
determination of whether or not items and services met the requirements for Medicare coverage 
under Section 1862(a)(1)(A) of the Social Security Act (the reasonable and necessary clause).  
That is, to be eligible to be covered (e.g., to have a benefit category determination) under 
Medicare, the device must be reasonable and necessary for the diagnosis or treatment of an 
illness or injury, or to improve the functioning of a malformed body member.2  
 
Under the 1995 CMS final rule, Category A devices were devices believed to be in class III for 
which absolute risk of the device type had not yet been established.  That is, initial questions 
of safety and effectiveness had not been resolved and FDA was unsure whether the device type 
could be safe and effective.  The IA contained two sub-categories which provided criteria 
indicating that a given device met this standard and should be placed into Category A: those 
devices for which no marketing application had been approved through the premarket approval 
(PMA) process for any indication for use, and devices that would otherwise be a Category B 
(discussed below), but had undergone significant modification for a new indication or use.  An 
example of a significant modification might be the addition of a drug to a legally marketed 
device where the drug previously had not been used on this type of device. 
                                                           
2 Implementation of the FDA/HCFA Interagency Agreement Regarding Reimbursement Categorization of 
Investigational Devices, Att. A Interagency Agreement, Att. B Criteria for Categorization of Investigational 
Devices, & Att. C List. #D95-2 (IDE Guidance Memorandum #95-2, Sept. 15, 1995), available at 
https://www.fda.gov/RegulatoryInformation/Guidances/ucm080302.htm. 
  
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  Contains Nonbinding Recommendations 
 
 
 
Under the 1995 CMS final rule, Category B devices were those devices believed to be in Class I 
or II, or devices believed to be in Class III for which the incremental risk was the primary risk in 
question.  That is, with respect to Category B devices, the underlying questions of safety and 
effectiveness of that device type had been resolved, or it was known that the device type could be 
safe and effective because, for example, other manufacturers had obtained FDA approval for that 
device type.  The IA identified six sub-categories of investigational devices that were of a device 
type for which the underlying questions of safety and effectiveness had been resolved and, thus, 
should be placed in Category B.  Under the IA, Category B devices included those that were 
under investigation to demonstrate substantial equivalence to a predicate device (legally 
marketed device) through the 510(k) process and devices comparable to a PMA-approved 
device.  Several examples of Category A and B devices can be found later in this document.   
 
Importantly, CMS and FDA both recognized that experience in categorizing devices might 
require changes to the IA.3   
 
2013 Amendment to 42 CFR 405 Subpart B 
 
CMS, with FDAs concurrence, published a final rule in the FR on December 10, 2013 (78 FR 
74230, 74809) that, among other things, modified the definitions for Category A and Category B.  
These definitions can be found in the Code of Federal Regulations (CFR) at 42 CFR 405.201:   
 
Category A (Experimental)  
42 CFR 405.201(b):  ...a device for which absolute risk of the device type has not been 
established (that is, initial questions of safety and effectiveness have not been resolved) and the 
FDA is unsure whether the device type can be safe and effective. 
 
Category B (Nonexperimental/investigational)  
42 CFR 405.201(b):  ...a device for which the incremental risk is the primary risk in question 
(that is, initial questions of safety and effectiveness of that device type have been resolved), or it 
is known that the device type can be safe and effective because, for example, other 
manufacturers have obtained FDA premarket approval or clearance for that device type. 
 
CMS uses FDAs categorization determination as a factor in evaluating whether or not an IDE 
device receives Medicare coverage.  Medicare may make payment for an investigational device 
and routine care items and services furnished in an FDA-approved Category B 
(Nonexperimental/Investigational) IDE study if CMS (or its designated entity) determines, prior 
to the submission of the first related claim, that the Medicare coverage IDE study criteria in 42 
CFR 405.212 are met.4  If the criteria are not met for a Category B device, neither the device nor 
other elements of the study will be covered.  With respect to Category A devices, if CMS (or its 
designated entity) determines that Medicare coverage IDE study criteria in 42 CFR 405.212 are 
met, Medicare may cover only routine care items and services furnished in an FDA-approved 
                                                           
3 The IA was published as an addendum to the final rule in 1995.  The FR noted that: As experience is gained in the 
categorization process, this addendum may be modified.  60 FR at 48419. 
4 42 CFR 405.211(b). 
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  Contains Nonbinding Recommendations 
 
 
Category A (Experimental) IDE study, but not the device itself.5  In other words, Medicare 
cannot cover device expenses with respect to studies involving devices that FDA has categorized 
as Category A (Experimental).  
 
Reasons for Modification of the Previous FDA Policy 
 
In the more than twenty years since the IA was signed, FDA has received a number of IDEs 
which do not easily fit into any of the eight sub-categories identified in the IA.   
 
In 2013, FDA published a final guidance document entitled Investigational Device Exemptions 
(IDEs) for Early Feasibility Medical Device Clinical Studies, Including Certain First in Human 
(FIH) Studies (available at 
https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocumen
ts/ucm279103.pdf).  That document provides guidance on the development and review of IDE 
applications for early feasibility studies (EFS) of significant risk devices.  EFS are feasibility 
studies that are very small in size and allow for early clinical evaluation of devices that may not 
be a final design.  They are intended to provide proof of principle and initial clinical study data.  
Traditional feasibility studies, on the other hand, are completed with a device design that is near-
final or final and are commonly used to capture preliminary safety and effectiveness information 
which may be used to inform a pivotal study design.  They are typically larger than EFS.  The 
general term feasibility studies may refer to EFS or traditional feasibility studies.  Pivotal 
studies are clinical investigations designed to collect definitive evidence of the safety and 
effectiveness of a device for a specified intended use, typically in a statistically justified number 
of subjects.  The previous FDA policy regarding reimbursement categorization did not 
adequately articulate categorization criteria that are relevant to certain feasibility studies, 
particularly those for devices similar to approved devices but with modifications which raise 
significant new safety questions.  As a result of this, and the recent increase in EFS submissions 
subsequent to the publication of the guidance document referenced above, FDA has determined 
that additional clarification of FDAs approach to these categorization criteria is warranted.  It is 
important to note that the category designation is made independent of study type and instead is 
based on the criteria described in this document.  
 
In addition to the above consideration, there are situations when adequate data are provided to 
resolve initial questions of safety and effectiveness (e.g., data from a feasibility study becomes 
available) and, therefore, it is appropriate to change the device category for subsequent studies of 
the same device from Category A to Category B.  In these circumstances, a device that had 
previously been categorized as experimental could now be considered 
nonexperimental/investigational.  However, the IA did not describe a pathway for changing 
categorization from Category A to Category B when approving subsequent studies for the same 
device.  In order to outline a mechanism to revisit the categorization of IDE devices when new 
information is gathered, the previous FDA policy for categorization of IDE devices is being 
modified.  
 
                                                           
5 42 CFR 405.211(a). 
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  Contains Nonbinding Recommendations 
 
 
Lastly, in its changes to the regulations (42 CFR 405 Subpart B), effective January 1, 2015, 
CMS, with FDAs concurrence, added criteria for coverage of IDE devices within CMS 
approved studies.  This was a change from local Medicare Administrative Contractor (MAC) 
review.  The change to a centralized IDE review further reinforced the need for CMS and FDA 
to revisit the policy that FDA used to categorize IDE devices.  CMS and FDA recognized the 
need to revise their shared understanding regarding the categorization of IDE devices to help 
ensure that reimbursement of devices will not be precluded due to an inappropriate 
reimbursement categorization determination.  Rather than amending their 1995 IA, FDA and 
CMS entered into an MOU on December 2, 2015 that became effective on June 2, 2016.  The 
policies and framework in this guidance represent the Agencys current thinking on 
categorization.  
III.  FDA Interpretation of Medicare Coverage Categories A 
and B 
 
After receipt of an IDE application, FDA will determine whether the sponsor has provided 
enough information to support initiation of the clinical study.  An IDE application is approved, 
or approved with conditions, if FDA has determined that the sponsor has provided adequate 
data to support initiation of a human clinical study, no subject protection concerns preclude 
initiation of the investigation, and the benefit-risk profile is sufficiently favorable to justify 
enrollment.6 A study which has been approved or approved with conditions may be staged such 
that preliminary data can be reviewed prior to full patient enrollment.  FDA intends to use the 
criteria described below to assign a device to Category A or B when the IDE is approved or 
approved with conditions.  Please refer to Appendix A for a flowchart depicting the decision-
making process. 
 
Category A: Experimental 
 
42 CFR 405.201(b):  ...a device for which absolute risk of the device type has not been 
established (that is, initial questions of safety and effectiveness have not been resolved) and the 
FDA is unsure whether the device type can be safe and effective.   FDA intends to consider a 
device to be in Category A if one or more of the following three criteria are met: 
 
  No PMA approval, 510(k) clearance, or De Novo request has been granted for the 
proposed device or similar devices, and data on the proposed device or other similar 
devices do not resolve initial questions of safety and effectiveness and FDA is unsure 
whether the device type can be safe and effective.   
 
  The proposed device is being studied for a new indication, or new intended use, for 
which information from the proposed or a similar device related to the previous 
indication or intended use does not resolve initial questions of safety and effectiveness.  
                                                           
6 For more information on how IDE Decisions are made please refer to the FDA Guidance document FDA 
Decisions for Investigational Device Exemption Clinical Investigations, available at 
https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm279107.pdf. 
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  Contains Nonbinding Recommendations 
 
 
Available non-clinical and/or clinical data on the proposed device or similar devices 
relative to the new indication or intended use also do not resolve these questions and 
FDA is unsure whether the device type can be safe and effective.  
 
  The proposed device has different technological characteristics compared to a legally 
marketed device, and information related to the marketed device does not resolve initial 
questions of safety and effectiveness for the proposed device.  Available non-clinical 
and/or clinical data on the proposed device or similar devices also do not resolve these 
questions and FDA is unsure whether the device type can be safe and effective. 
 
Category B: Nonexperimental/Investigational 
 
42 CFR 405.201(b):  ...a device for which the incremental risk is the primary risk in question 
(that is, initial questions of safety and effectiveness of that device type have been resolved), or it 
is known that the device type can be safe and effective because, for example, other 
manufacturers have obtained FDA premarket approval or clearance for that device type. 
 
FDA intends to consider a device to be in Category B if one or more of the following three 
criteria are met: 
 
  No PMA approval, 510(k) clearance, or De Novo request has been granted for the 
proposed device or similar devices; however, available information (e.g., feasibility study 
data) from the proposed device or a similar device resolve the initial questions of safety 
and effectiveness.  
 
  The proposed device is being studied for a new indication or new intended use; however, 
information from the proposed or a similar device related to the previous indication or 
intended use resolves the initial questions of safety and effectiveness.  In some cases, 
additional non-clinical and/or clinical data on the proposed device may also have been 
used to resolve these questions.    
 
  The proposed device has similar technological characteristics compared to a legally 
marketed device, and information related to the marketed device resolves the initial 
questions of safety and effectiveness for the proposed device.  In some cases, additional 
non-clinical and/or clinical data on the proposed device may also have been used to 
resolve these questions.  
 
IV.  Considerations When Changing from Category A to B 
 
As mentioned previously in this document, there are situations in which clinical and/or non-
clinical evaluations provide adequate data to resolve initial questions of safety and effectiveness 
and, therefore, it is appropriate to change the device category from Category A to Category B.  
Data can come from different sources and may become available at different points in time.  
Therefore, a category change from A to B could occur in a variety of circumstances and the 
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change may or may not coincide with the completion of a clinical study, or a stage of a clinical 
study, on the investigational device.  
 
One situation when a categorization change would be appropriate is when a completed study in 
which the device was designated as Category A has resulted in clinical data that resolve the 
initial questions of safety and effectiveness.  In this case, the device should be designated as 
Category B in the subsequent study. 
 
Another situation where a category change may be warranted is when an IDE study receives a 
staged approval or staged approval with conditions. 7 In a staged approval, FDA may grant IDE 
approval or approval with conditions for a portion of the intended study cohort, enabling certain 
outstanding questions to be answered concurrently with enrollment in this initial stage cohort.  
The sponsor will be permitted to expand enrollment once an IDE supplement containing the 
necessary additional information is submitted to FDA and found to be acceptable.  In cases in 
which the device has been designated as Category A because there are questions relevant to 
initial safety and effectiveness, data gathered from the first (or subsequent) enrollment stage(s) 
may resolve initial questions of safety and effectiveness such that the device category may be 
changed from Category A to Category B during continued study in the full study subject cohort.   
 
FDA will evaluate whether adequate data are present to resolve the initial questions of safety and 
effectiveness; a categorization decision will be made upon study approval (for a new study), 
upon submission of a request to change the category, or upon review of other IDE supplements 
related to the study (e.g., study expansion request).   FDA assigns a category independently for a 
new study and may initiate a categorization change either independently or in response to a 
sponsors request.  A request to change the IDE category (either from Category A to B or 
Category B to A8) can be submitted at any time as an IDE supplement and FDA intends to render 
a decision within thirty days.  The supplement should include data which would support meeting 
the criteria as identified in 42 CFR 405.201(b).  Examples of data that may support a change 
from Category A to Category B can include but are not limited to:  
 
  Peer-reviewed studies on the same or a similar device.  
  Premarket or postmarket data from studies conducted outside the U.S. on the same or a 
similar device.  
  Reference to commercialization of a device of a similar type.  
  Preliminary clinical data on the device (e.g., initial data from a staged study, feasibility 
study).  
  Additional non-clinical data on the same or a similar device may be included as 
supportive information.  
 
FDA also occasionally receives requests from study sponsors to change from Category B to 
Category A. In order to support a change from Category B to Category A, there should be 
                                                           
7 See FDA Decisions for Investigational Device Exemption Clinical Investigations at 
https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm279107.pdf. 
8 FDA expects most category changes to be from A to B as additional information about the device is obtained. 
However, the category designation may also change from B to A. 
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directly relevant new information which demonstrates that initial questions of safety and 
effectiveness have not been resolved.  For example, a comparison of the proposed device to a 
commercialized device of a similar type could be supplied along with an explanation to support 
why initial questions of safety and effectiveness related to the proposed device still remain that 
warrants a categorization change. 
 
The categorization decision will be included in the IDE (original or supplement) approval letter 
to the sponsor.  In addition to the formal communication by FDA to CMS, it is at the sponsors 
discretion to communicate to CMS when IDE categorization changes.  It should be noted that a 
categorization change for a given device will not automatically apply to similar devices.  
 
V.  Examples 
 
Category A: Experimental  
The list below provides examples of when a Category A determination may be appropriate, but it 
does not represent an exhaustive list of when a device should be classified as Category A.   
 
  A device is completely novel and has no, or limited, previous human use and there are 
initial questions of safety and effectiveness.  There is adequate non-clinical information 
to support initiation of an early feasibility study that will provide data to inform potential 
device design or procedural improvements. 
 
  A drug is added to a previously approved or cleared device.  While substantial 
information is known about the previously approved or cleared device, the drug has not 
previously been used on this type of device, and relevant non-clinical or clinical data are 
not available to address the initial questions of safety and effectiveness associated with 
the addition of the drug.  
 
  An already-approved or -cleared device is being evaluated for a new intended use or 
indication for which the device will be placed in a different anatomical location.  The 
devices technology is unchanged from what was initially approved or cleared.  While 
some non-clinical data on this device may be used to anticipate certain aspects of device 
performance, it is still uncertain as to whether the device can be safely placed, and be 
effective, in the new anatomical location.  Therefore, there are inadequate data to resolve 
the initial questions of safety and effectiveness relative to the new intended use or 
indication, and FDA is unsure whether or not the device type can be safe and effective.   
 
  The initial question of safety has been answered with the submission of non-clinical data 
and short-term clinical data from a small study.  However, additional performance data 
will be needed to resolve initial questions related to effectiveness.  Therefore, this device 
will be designated as Category A.  
 
  The initial question of effectiveness has been answered with the submission of data that 
demonstrate similar performance to a previously approved device.  There is inadequate 
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evidence to resolve initial questions related to safety because this will require follow up 
in a clinical study; however, the benefit-risk profile supports initiation of a study. 
 
Category B:  Nonexperimental/Investigational 
The list below provides examples of when a Category B determination may be appropriate, but it 
does not represent an exhaustive list of when a device should be classified as Category B. 
  
  The insertion system of an approved device has been modified to improve ease of use for 
the clinician.  Non-clinical test data resolved initial questions of safety and effectiveness 
related to this change; however, confirmatory clinical information about the device 
performance is required due to the inherent differences between the non-clinical test 
environment and the clinical setting.   
 
  Adequate data have been gathered from non-clinical testing, and the clinical results of a 
feasibility study such that initial questions of safety and effectiveness have been resolved.  
A pivotal study will be initiated to provide the primary clinical evidence for the safety 
and effectiveness of the device in support of a future marketing application.  
  
  A new device will be studied for an indication for which substantial safety and 
effectiveness information exists from other similar device(s) of the same type that are 
used for the same or a similar indication.  Clinical information from similar devices and 
non-clinical test data for the new device that have been provided can answer initial safety 
and effectiveness questions regarding this indication. 
 
  A modification has been made to an approved device in order to improve its 
performance.  Non-clinical and clinical data available from the previous version of the 
device, along with additional testing on the modified device, resolved initial questions of 
safety and effectiveness.  The purpose of the study will be to gather further data regarding 
device performance for this modified version of the device. 
 
  New device sizes will be added to a product matrix for an approved device. Initial 
questions of safety and effectiveness have been resolved based on experience with the 
approved device, and it is generally understood how the new device sizes will perform.  
The new device sizes will be evaluated in a clinical study such that confirmatory safety 
and effectiveness information relevant to these sizes can be gathered. 
 
  An approved device will be evaluated in a new patient population.  Non-clinical and 
clinical data from use in the previous patient population resolved initial questions of 
safety and effectiveness for the new patient population.  The new study to be conducted 
will provide further data regarding device performance for this new patient population. 
 
  An approved device will be evaluated for a new indication.  Data exist on the approved 
device for a similar indication, and non-clinical data have also been supplied such that the 
initial questions of safety and effectiveness related to the new indication have been 
resolved.  The new study to be conducted will provide further data regarding device 
performance for this new indication. 
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Change from Category A to Category B 
If the device was previously designated as Category A, but the initial questions of safety and 
effectiveness of the device have since been resolved, it may be appropriate to change the 
Category from A to B.  The list below provides examples of when a change from Category A to 
Category B may be appropriate, but it does not represent an exhaustive list of when a device may 
change from Category A to Category B. 
 
  A novel insertion procedure will be used to place an already-approved or -cleared device, 
and there are initial questions of safety and effectiveness regarding the novel insertion 
procedure that have not been resolved.  In this case, these questions of safety and 
effectiveness may be answered in a short timeframe with a limited number of subjects in 
the context of a larger clinical study.  Therefore, the device will be evaluated in a staged 
clinical study where the first stage falls under Category A.  If the initial questions of 
safety and effectiveness are resolved, and the study continues, the device may be re-
categorized to Category B. 
 
  Adequate data have been gathered on a device from non-clinical testing and an early 
feasibility study has been conducted within the U.S., such that initial questions of safety 
and effectiveness have been resolved.  Additional data are needed to help inform a 
pivotal study design; therefore, a traditional feasibility study will be initiated.  Although 
the EFS was originally designated as Category A, adequate data as described above have 
since been gathered (in the EFS) to support a change to Category B for the traditional 
feasibility study. 
 
  A device is currently being evaluated in a clinical study and has been designated 
Category A.  While the study is being conducted, clinical study results for similar devices 
become available which resolve initial questions of safety and effectiveness for the 
device.  This information will be used to support a categorization change from Category 
A to Category B for the device evaluated in the ongoing clinical study.   
VI.  Conclusions  
 
FDA categorizes IDE devices based on whether available data demonstrate that initial questions 
of safety and effectiveness have been resolved.  This guidance document describes the process 
and information that will be used to help determine the appropriate category for a device to be 
studied.  This guidance document also describes when it is appropriate to change the device 
category from Category A to Category B.   
 
The categorization of IDE devices is used by CMS as part of its determination of which devices 
meet the requirements for Medicare coverage under Section 1862 (a)(1)(A) of the Social 
Security Act (the reasonable and necessary clause).  IDE device categorization is only part of 
the information used to determine coverage by CMS.  Please refer to the website Medicare 
Coverage Related to Investigational Device Exemption (IDE) Studies 
(https://www.cms.gov/medicare/coverage/IDE/index.html) for guidance on requesting coverage 
and for contact information. 
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Appendix A: Category Decision Flowchart 
 
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