How FDA classifies medical devices

FDA assigns a device to class I, class II or class III according to the level of regulatory control needed to provide reasonable assurance of its safety and effectiveness. The class attaches to a generic type of device and is published in a classification regulation in parts 862 through 892 of 21 CFR, which states the identification of the type and its class.¹ The identification gives the general description and intended use of the type. A product that falls within an identification takes the class stated in that regulation, together with any exemptions and special controls the regulation sets.

What the three classes mean

Class I covers devices subject only to the general controls authorized by or under the following sections of the Federal Food, Drug, and Cosmetic Act.

• 501
• 502
• 510
• 516
• 518
• 519
• 520

A device is in class I where general controls are sufficient to provide reasonable assurance of safety and effectiveness. Class I also covers a device for which information is insufficient to determine that general controls suffice or to establish special controls, where the device is neither life-supporting nor life-sustaining, is not for a use of substantial importance in preventing impairment of human health and presents no potential unreasonable risk of illness or injury.¹

Class II covers devices that are or will be subject to special controls. A device is in class II where general controls alone are insufficient and there is enough information to establish special controls. Special controls include the following.¹

• performance standards
• performance testing
• postmarket surveillance
• patient registries
• guidelines
• recommendations
• other actions the Commissioner considers necessary

For a device represented for use in supporting or sustaining human life, the Commissioner identifies the special controls that give adequate assurance of safety and effectiveness and describes how they do so.¹

Class III covers devices for which premarket approval under section 515 is or will be required. A device is in class III where information is insufficient to determine that general controls, or general controls with special controls, would provide reasonable assurance of safety and effectiveness. The device must in addition be life-supporting or life-sustaining, be for a use of substantial importance in preventing impairment of human health, or present a potential unreasonable risk of illness or injury.¹

How a device type is defined

A generic type of device is a grouping of devices that do not differ significantly in any of the following.

• purpose
• design
• materials
• energy source
• function
• any other feature related to safety and effectiveness

The grouping also requires that similar regulatory controls suffice for the devices within it.¹ Classification therefore turns on the characteristics of the type, and the intended use stated in the identification is part of what fixes the boundary of that type.

Two definitions carry particular weight. An implant is a device placed into a surgically or naturally formed cavity of the human body, and it counts as an implant for classification purposes only if it is intended to remain implanted continuously for 30 days or more, unless the Commissioner determines otherwise to protect human health.¹ A life-supporting or life-sustaining device is one that is essential to, or that yields information essential to, the restoration or continuation of a bodily function important to the continuation of human life.¹

Implants and life-supporting or life-sustaining devices

A classification panel recommends class III for any implant or life-supporting or life-sustaining device unless it determines that class III is not necessary to provide reasonable assurance of safety and effectiveness.¹ Where the panel recommends a lower class, its recommendation must state the reasons and identify the risks to health presented by the device. Where the recommendation is class II, the panel must describe the special controls it believes necessary and explain how they provide the assurance.¹

The same presumption binds the Commissioner. An order or regulation placing such a device outside class III must carry a full statement of reasons, which may take the form of concurrence with the panel together with supporting documentation and data meeting § 860.7.¹

The evidence FDA weighs

Classification decisions rest on the factors in § 860.7(b).¹

• the persons for whose use the device is represented or intended
• the conditions of use including those in labeling or advertising
• the probable benefit to health weighed against probable injury or illness
• the reliability of the device

A manufacturer may submit any form of evidence, and FDA relies only on valid scientific evidence in deciding whether there is reasonable assurance that the device is safe and effective.¹

Valid scientific evidence includes well-controlled investigations, partially controlled studies, studies and objective trials without matched controls, well-documented case histories conducted by qualified experts, and reports of significant human experience with a marketed device.¹ Isolated case reports, random experience, reports lacking detail for scientific evaluation and unsubstantiated opinions fall outside that definition, though FDA may consider such information in identifying a device of questionable safety or effectiveness.¹ The responsibility to assure that adequate valid scientific evidence exists rests on each manufacturer and importer, and a failure to present it may support a determination that the device belongs in class III.¹

Devices marketed before 28 May 1976

Subpart B of Part 860 governs the original classification of a generic type of device that was in commercial distribution before 28 May 1976. Such a device is classified by regulation into class I, class II or class III according to the level of control required.¹ The Commissioner refers the device to the appropriate classification panel, which reviews safety and effectiveness under § 860.7 and gives interested persons an opportunity to submit data and views.¹

The panel’s recommendation includes a summary of its reasons, a summary of the underlying data and an identification of the risks to health presented by the device.¹ The Commissioner publishes the recommendation in the Federal Register with a proposed classification regulation, takes comment and then issues a final regulation covering the device and others of that generic type.¹ Panel recommendations are preliminary until the Commissioner has reviewed them and published a proposed regulation.¹

Devices first marketed after 28 May 1976

A device first introduced or delivered for introduction into interstate commerce for commercial distribution after 28 May 1976 sits in class III by operation of section 513(f)(1). Four situations take a device out of that statutory class III.¹

• it is substantially equivalent to a device in commercial distribution before that date that had not been regulated as a new drug
• it is substantially equivalent to a later device already classified into class I or class II
• the Commissioner has classified it into class I or class II on a reclassification petition
• it is classified under a De Novo request

Substantial equivalence is decided in the premarket notification process under section 510(k). Guidance from the Center for Devices and Radiological Health sets out the agency’s approach to evaluating substantial equivalence in premarket notifications, and that guidance states current FDA thinking without binding FDA or industry.²

De Novo classification into class I or class II

The De Novo process gives a route to class I or class II for a device type where no legally marketed device exists on which to base a substantial equivalence review, provided the device meets the class I or class II criteria in section 513(a)(1) and § 860.3.¹ A De Novo request may be submitted for a single device type after a not substantially equivalent determination on a 510(k), or where the person determines there is no legally marketed device on which to base substantial equivalence.¹

Section 860.220 lists the required content, including the following.¹

• the indications for use
• a device description
• a classification summary
• a summary of probable risks and proposed mitigations
• the recommended class
• the technical sections containing nonclinical, software and clinical data

Where the recommendation is class II, the request must include an initial draft proposal for special controls and a description of how they provide reasonable assurance of safety and effectiveness.¹ FDA grants the request by order unless one of the grounds in § 860.260(c) applies, and within 30 days of a granting order it publishes a notice of the classification order in the Federal Register, including any special controls.¹ The grounds for declining include that the device type has already been classified, that the product does not meet the device definition in section 201(h) and is not a combination product, and that the labeling does not comply with parts 801 and 809.¹

Exemptions from premarket notification and other requirements

A regulation or order classifying a device into class I specifies which requirements of sections 510, 519 and 520(f) the device is exempt from, with the reasons. For class II, it specifies whether the device is exempt from premarket notification under section 510.¹ The Commissioner grants such exemptions only on a determination that the requirements are not necessary to provide reasonable assurance of safety and effectiveness.¹ Section 860.15 was amended on 4 December 2025 to describe section 520(f) as the good manufacturing practice requirements of the quality management system regulation.¹

An exemption from premarket notification carries limits. For clinical chemistry and clinical toxicology devices, § 862.9 confines the exemption to devices with existing or reasonably foreseeable characteristics of commercially distributed devices within the generic type. For in vitro diagnostic devices, it confines the exemption to cases where misdiagnosis would not be associated with high morbidity or mortality.³ A premarket notification is still required where the device is intended for a use different from that of a legally marketed device in the type, or where a modified device operates using a different fundamental scientific technology.³ Section 862.9(c) lists further intended uses that require a submission, including the following.³

• use in diagnosis, monitoring or screening of neoplastic diseases
• screening or diagnosis of genetic disorders
• diabetes management
• near patient testing

Reclassification of a classified device

A manufacturer or importer may petition under § 860.123 to reclassify a device held in class III by operation of section 513(f)(1). Within 30 days of filing, the Commissioner notifies the petitioner of deficiencies that prevent a decision and allows the petition to be supplemented.¹ Where the petition is referred to a classification panel, the panel submits its recommendation within 90 days of referral, and the Commissioner denies or approves the petition within 90 days of receiving that recommendation and no more than 210 days after the petition was filed.¹

The Commissioner may also reclassify on the Commissioner’s own initiative by administrative order, moving a device from statutory class III to class II where special controls are necessary and sufficient, or to class I where general controls alone would suffice.¹ That proceeding starts with a proposed reclassification order published in the Federal Register for comment, may involve panel consultation, and ends with a final administrative order.¹ An order moving a device from class III to class II may establish the special controls.¹

Questions people also ask

What is the difference between general controls and special controls?

General controls are the controls authorized by or under certain sections of the Federal Food, Drug, and Cosmetic Act.¹ Those sections are 501, 502 and 510, then 516 and 518, then 519 and 520. They cover the following.

• adulteration
• misbranding
• registration
• listing
• premarket notification
• banned devices
• notification and other remedies
• records
• reports
• unique device identification

Special controls are the additional controls necessary to provide reasonable assurance of safety and effectiveness for a class II generic type. They include the following.¹

• performance standards
• performance testing
• postmarket surveillance
• patient registries
• guidelines
• recommendations

Is a new device with no equivalent automatically class III?

A device first marketed after 28 May 1976 is in class III by operation of section 513(f)(1) unless one of the four exceptions in § 860.134(a) applies.¹ One of those exceptions is classification under a De Novo request submitted under section 513(f)(2), which is available where there is no legally marketed device on which to base a substantial equivalence review and the device meets the class I or class II criteria.¹

Does an exempt classification regulation remove the need for a 510(k) in every case?

For devices in part 862, the exemption reaches only devices with existing or reasonably foreseeable characteristics of commercially distributed devices within the generic type, and for in vitro diagnostics only where misdiagnosis would not be associated with high morbidity or mortality.³ A premarket notification remains required for a different intended use, for a different fundamental scientific technology, and for the in vitro diagnostic intended uses listed in § 862.9(c).³

How does FDA treat an implant during classification?

A classification panel recommends class III for any implant, and the Commissioner classifies it into class III, unless a determination is made that class III is not necessary to provide reasonable assurance of safety and effectiveness.¹ For classification purposes an implant is a device placed into a surgically or naturally formed cavity and intended to remain implanted continuously for 30 days or more, unless the Commissioner determines otherwise to protect human health.¹

What does a De Novo request have to say about risk?

Section 860.220(a)(9) requires a summary of the probable risks to health associated with use of the device that are known or should reasonably be known to the requester, together with the proposed mitigations.¹ Where the recommended class is II, the mitigations include proposed special controls for each risk, and each mitigation involving performance testing or labeling must reference the supporting information in the request.¹

Footnotes

1. 21 CFR Part 860, Medical Device Classification Procedures. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-H/part-860 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹ ↩²² ↩²³ ↩²⁴ ↩²⁵ ↩²⁶ ↩²⁷ ↩²⁸ ↩²⁹ ↩³⁰ ↩³¹ ↩³² ↩³³ ↩³⁴ ↩³⁵ ↩³⁶ ↩³⁷ ↩³⁸ ↩³⁹ ↩⁴⁰ ↩⁴¹ ↩⁴² ↩⁴³ ↩⁴⁴

2. FDA guidance, Center for Devices and Radiological Health, The 510(k) Program: Evaluating Substantial Equivalence in Premarket Notifications [510(k)]: Guidance for Industry and Food and Drug Administration Staff. 28 July 2014. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/510k-program-evaluating-substantial-equivalence-premarket-notifications-510k ↩

3. 21 CFR 862.9, Limitations of exemptions from section 510(k) of the Federal Food, Drug, and Cosmetic Act (the act). https://www.ecfr.gov/current/title-21/chapter-I/subchapter-H/part-862/subpart-A/section-862.9 ↩ ↩² ↩³ ↩⁴ ↩⁵