What is a medical device?

21 USC 321(h) 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. The term ‘‘device’’ does not include software functions excluded pursuant to section 360j(o) of this title.

Types of Device Studies

What is an investigational medical device?

21 CFR 812.3 Definitions2

(g) Investigational device means a device, including a transitional device, that is the object of an investigation.

(h) Investigation means a clinical investigation or research involving one or more subjects to determine the safety or effectiveness of a device.

(i) Investigator means an individual who actually conducts a clinical investigation, i.e., under whose immediate direction the test article is administered or dispensed to, or used involving, a subject, or, in the event of an investigation conducted by a team of individuals, is the responsible leader of that team.

(p) Subject means a human who participates in an investigation, either as an individual on whom or on whose specimen an investigational device is used or as a control. A subject may be in normal health or may have a med- ical condition or disease.

By applying the definitions (right), it becomes clear that simply using a device as part of a study does not make the device investigational. For example, if an non-invasive, unapproved device is used to make measurements as part of a study, but the study is not about the device, then the device is not an investigational device for the purposes of that study. For example, if an investigator wishes to use an unapproved device to measure cerebral blood flow but the study is not about the device (not assessing the safety or effectiveness of the device), then for that study, the unapproved device would not be investigational. Whereas the device would be an investigational device when used in a study designed to assess the feasibility and safety of making cerebral blood flow measurements during cardiac surgery.

Following the flow diagram (below) and definitions on the Device Regulation and Classification page, the sponsor/investigator should first determine if the study meets the definition of a clinical investigation of an investigational device. If the study is a clinical investigation of an investigational device, then the investigator must determine how to apply the FDA's device regulations. The Investigational Device Exemptions (IDE) regulations (21 CFR 812) describe three types of device studies: (1) exempt investigations, (2) investigations of significant risk (SR) devices, and (3) investigations of nonsignificant risk (NSR) devices.

The regulatory requirements vary, depending on which of the three types of device studies is involved. Humanitarian Use Devices, when used in accordance with their label - under a Humanitarian Device Exemption (HDE) - are a special case and follow different regulations. These are discussed on a separate page.

Regulatory Pathway for Devices

Exempted Investigations

With the exception of 21 CFR 812.119, the rest of the IDE regulations do not apply to device studies that meet the criteria for an exempted investigation under 21 CFR 812.2 (c). They also do not require the FDA, the sponsor, the investigator or the IRB to make an NSR or SR determination.

Exempted investigations include investigations involving one of the following:

  1. A device, other than a transitional device, in commercial distribution immediately before May 28, 1976, when used or investigated in accordance with the indications in labeling in effect at that time.
  2. A device, other than a transitional device, introduced into commercial distribution on or after May 28, 1976, that FDA has determined to be substantially equivalent to a device in commercial distribution immediately before May 28, 1976, and that is used or investigated in accordance with the indications in the labeling FDA reviewed under subpart E of part 807 in determining substantial equivalence.
  3. A diagnostic device, if the sponsor complies with applicable requirements in 809.10(c) and if the testing: (Comment: this is the most frequent type of exempted investigation submitted to the CHOP IRB.)
    1. Is noninvasive,
    2. Does not require an invasive sampling procedure that presents significant risk,
    3. Does not by design or intention introduce energy into a subject, and
    4. Is not used as a diagnostic procedure without confirmation of the diagnosis by another, medically established diagnostic product or procedure.
  4. A device undergoing consumer preference testing, testing of a modification, or testing of a combination of devices if the device(s) are legally marketed device(s) (that is, the devices have an approved PMA, cleared Premarket Notification 510(k), or are exempt from 510(k)) AND if the testing is not for the purpose of determining safety or effectiveness and does not put subjects at risk.
  5. A device intended solely for veterinary use.
  6. A device shipped solely for research on or with laboratory animals and labeled in accordance with 812.5(c).
  7. A custom device as defined in 812.3(b), unless the device is being used to determine safety or effectiveness for commercial distribution.

Significant Risk Devices

Under 21 CFR 812.3(m), an SR device means an investigational device that:

  1. Is intended as an implant and presents a potential for serious risk to the health, safety, or welfare of a subject;
  2. Is purported or represented to be for use supporting or sustaining human life and presents a potential for serious risk to the health, safety, or welfare of a subject;
  3. Is for a use of substantial importance in diagnosing, curing, mitigating, or treating disease, or otherwise preventing impairment of human health and presents a potential for serious risk to the health, safety, or welfare of a subject; or
  4. Otherwise presents a potential for serious risk to the health, safety, or welfare of a subject.

A SR device must follow all of the IDE Regulations at 21 CFR 812 and the study must be conducted under an Investigational Device Exemption (IDE) application approved by the FDA before the investigation begins.

Examples of SR Devices
  • Catheters for General Hospital Use - except for conventional long-term percutaneous, implanted, subcutaneous and intravascular
  • Surgical Lasers for use in various medical specialties
  • Respiratory Ventilators and new modes of ventilation
  • Cardiac Assist, Bypass and ECMO Devices
  • Cardiac Pacemaker/Pulse Generators
  • Cardiopulmonary Resuscitation (CPR) Devices
  • Intravascular Stents, Percutaneous Transluminal Angioplasty Catheters, Heart Valves
  • Implantable Prostheses and Vascular Devices (new devices)
  • Dialysis Delivery Systems
  • Sutures
  • Infusion Pumps (implantable and closed-loop - depending on the infused drug)

Non-Significant Risk Devices

A NSR device is any device that doesn't meet the definition of a SR device. Studies involving an NSR need only follow the abbreviated device regulations at 21 CFR 812.2(b). It the sponsor's responsibility to provide the IRB with the following:

  • their determination that the device is NSR,
  • the reasons why it has come to this conclusion,
  • information that needed to allow the IRB to evaluate the risk of using the device in the proposed study,
  • a description of the device,
  • the protocol and any other information that the IRB requires

At the time of its review the IRB must review the investigator/sponsor's NSR determination and either agree or disagree. In addition, the IRB must review and approve the study using the FDA's Human Subjects Research Regulations and IRB regulations at 21 CFR 50 and 56.

Examples of NSR Devices
  • Contact Lens Solutions
  • Conventional Gastroenterology and Urology Endoscopes and/or Accessories
  • Conventional General Hospital Catheters
  • Conventional Implantable Vascular Access Devices (Ports)
  • Conventional Laparoscopes, Culdoscopes, and Hysteroscopes
  • Electroencephalography (e.g., new recording and analysis methods, enhanced diagnostic capabilities, measuring depth of anesthesia if anesthetic administration is not based on device output)
  • Externally Worn Monitors for Insulin Reactions
  • Functional Non-Invasive Electrical Neuromuscular Stimulators
  • General Urological Catheters (e.g., Foley and diagnostic catheters) for short term use (
  • Low Power Lasers for treatment of pain
  • Magnetic Resonance Imaging (MRI) Devices within FDA specified parameters
  • Ob/Gyn Diagnostic Ultrasound within FDA approved parameters

Related FDA Guidance Documents: Devices