FDA Definition of a Medical Device

The definition of medical device was first formalized under the Food, Drug and Cosmetic Act in 1938. Today the Food, Drug, and Cosmetic Act (FD&C Act) defines a medical device as:

An instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, including a component part, or accessory which is:

(A) recognized in the official National Formulary, or the United States Pharmacopoeia, or any supplement to them,

(B) 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

(C) 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 520(o).

TLDR - a medical device is essentially anything, including software, that is intended to diagnose, prevent, or treat a disease or modify the body's structure or function by means other than a chemical action or being metabolized.

FDA Classification of Medical Devices

The Food and Drug Administration (FDA) has established classifications for approximately 1,700 different generic types of devices and grouped them into 16 medical specialties referred to as panels. Each of these generic types of devices is assigned to one of three regulatory classes based on the level of control necessary to assure the safety and effectiveness of the device. Classification is risk based, that is, the risk the device poses to the patient and/or the user is a major factor in the class it is assigned. Class I includes devices with the lowest risk and Class III includes those with the greatest risk.

The three classes and the requirements which apply to them are:

• Class I General Controls - With or Without Exemptions
• Class II General Controls and Special Controls - With or Without Exemptions
• Class III General Controls and Premarket Approval
  

Device classification depends on the intended use of the device and also upon indications for use. For example, a scalpel's intended use is to cut tissue. A subset of intended use arises when a more specialized indication is added in the device's labeling such as, "for making incisions in the cornea". Indications for use can be found in the device's labeling, and marketing materials.

Once the intended use is determined, a related device code can be identified. These device codes can be found in the FDA's Product Code Classification Database. Each generic device type is assigned a device code. If a relevant device code is not available, something very likely with SaMD products, then a De Novo application may be the premarket pathway. This is the premarket approval pathway for a truly novel device that does not have a predicate.

The class to which your device is assigned determines the type of premarketing submission/application required for FDA clearance to market. If your device is classified as Class I or II, and if it is not exempt, a 510k will be required for marketing. All devices classified as exempt are subject to the limitations on exemptions. For Class III devices, a premarket approval application (PMA) will be required.

Unless exempted, all classes of devices as subject to General Controls. General Controls are the baseline requirements of the Food, Drug and Cosmetic (FD&C) Act that apply to all medical devices, Class I, II, and III. These include the Medical Device Regulations under the 21 CFR 800 series.

Software as a Medical Device (SaMD)

The International Medical Device Regulators Forum (IMDRF) defines “Software as a Medical Device” (SaMD) as software intended to be used for one or more medical purposes that perform these purposes without being part of a hardware medical device. 

The IMDRF reasserts in their guidance that SaMD is a medical device and includes in-vitro diagnostic (IVD) medical devices.

SaMD is a software only device, capable of running on general purpose (non-medical purpose) computing platforms like PCs, tablets, and mobile devices. “Without being part of” means the software is not necessary for the hardware to function, software does not meet the definition of SaMD if its intended purpose is to drive a hardware medical device.

SaMD may be used in combination with other products including medical devices. It includes software that may be interfaced with other medical devices, including hardware medical devices and other SaMD software, as well as non-medical software.

Lesson Summary

The FDA defines a medical device as:

• An instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, including a component part, or accessory.
• Intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease, or to affect the structure or function of the body, excluding chemical actions or metabolism for primary intended purposes.

Device classification by the FDA:

• Three classes - Class I, Class II, Class III with varying controls and requirements where class I includes the lowest risk devices, and class III includes the highest risk devices.
• Classification is based on intended use and indications and determines the devices premarket submission/approval pathway.

Software as a Medical Device (SaMD):

• Defined by the International Medical Device Regulators Forum (IMDRF) as software performing medical purposes independently from hardware.
• SaMD can run on general-purpose platforms like PCs, tablets, and mobile devices but is not essential for the hardware to function.
• SaMD may be used with other medical products, including hardware medical devices and other SaMD software.