What are the Differences in the FDA Medical Device Classes?
The US FDA regulates all medical devices marketed in the US, which are grouped into three broad classes. Any medical device approved by the FDA is classified as either Class I, II, or III depending on the device's risk, invasiveness, and impact on the patient's overall health. But where are the lines drawn between each of these three classes, and why?
The US FDA's classification guidelines can be highly confusing to medical device manufacturers with limited exposure to the system. There is an enormous difference in the optimal path to market for manufacturers depending on how your device is grouped. Class I devices are subject to far fewer regulatory requirements than Class II or III devices.
By understanding the differences in the FDA medical device classes, you can understand how your device will be grouped. With this knowledge in hand, medical device manufacturers in the premarket stages can better prepare and allocate the resources needed for regulatory approval.
Differences between FDA Medical Device Classes
The FDA has classified over 1,700 distinct types of medical devices. The devices are organized in the Code of Federal Regulations (CFR) according to 16 specialties, such as Cardiovascular or Hematology devices. Classifying your medical device according to one of the 16 specialties is the first step to understanding whether you are manufacturing a Class I, II, or III medical device.
After classifying a device according to specialty, the FDA instructs manufacturers to proceed to premarket notification with knowledge of whether their device is exempt or not. Class I medical devices, the least risky and invasive category, are exempt from premarket notification processes. Specific class II devices are also exempt from premarket approval.
However, all devices regulated by the FDA are subject to current Good Manufacturing Practice (cGMP) requirements for registration, labeling, and quality. But how do you know if your device is Class I or II, and whether you’re required to undergo premarket notification?
The US FDA defines Class I devices as devices which are "not intended for use in supporting or sustaining life or of substantial importance in preventing impairment to human health, and they may not present a potential unreasonable risk of illness or injury."
These devices are the most common Class of devices regulated by the FDA, constituting 47 percent of approved devices on the market.
Class I devices have minimal contact with patients and low impact on a patient's overall health. In general, Class I devices do not come into contact with a patient's internal organs, the central nervous system, or cardiovascular system. These devices are subject to the fewest regulatory requirements.
Examples of Class I Devices:
- Electric Toothbrush
- Tongue Depressor
- Oxygen Mask
- Reusable Surgical Scalpel
- Hospital Beds
Bringing Class I Medical Devices to Market
Class I devices are the fastest and easiest to bring to market since they present the lowest amount of risk to the patient and are rarely critical to life-sustaining care. The majority of Class I devices are exempt from FDA requirements for Premarket Notification (510k) and Premarket Approval (PMA).
Class I devices are not exempt from FDA general controls, a series of commands which applies to Class I, II, and III medical devices. The provisions of this act address adulteration, misbranding, device registration, records, and good manufacturing practices. Medical device manufacturers who fall into Class A are still required to implement a quality management system and follow standards to ensure a quality product.
Class II medical devices are more complicated than Class I devices and present a higher category of risk because they are more likely to come into sustained contact with a patient. This can include devices which come into contact with a patient's cardiovascular system or internal organs, and diagnostic tools.
The FDA defines Class II devices as “devices for which general controls are insufficient to provide reasonable assurance of the safety and effectiveness of the device.”
Examples of Class II Medical Devices:
- Blood Pressure Cuffs
- Pregnancy Test Kits
- Blood Transfusion Kits
- Contact Lenses
- Surgical Gloves
- Absorbable Sutures
Bringing Class II Medical Devices to Market
Controls vary depending on the device, but according to the FDA, can include:
- Device performance
- Postmarket surveillance
- Patient registries
- Special labeling requirements
- Premarket data requirements
The majority of Class II devices are FDA approved for the market through the Premarket Notification, or 510(k) process.
Class II devices are subject to the same General Controls mentioned above, but the FDA defines them as being “devices for which general controls are insufficient to provide reasonable assurance of the safety and effectiveness of the device.” For that reason, Class II devices are also subject to Special Controls. These regulations depend on the device and may include special labeling requirements, patient registries, and performance standards.
Most Class II devices come to market using the Premarket Notification (510k) process. The 510(k) is a complex application to the FDA, which demonstrates that a device is safe and effective by demonstrating that the device is equivalent to another device which is on the market.
This process involves showing "substantial equivalence" to another device which is known in FDA parlance as "the predicate." This doesn't mean the devices need to be identical, but they require significant similarities in use, design, materials, labeling, standards, and other characteristics.
The FDA released an exemption list in early 2018 which exempts over 800 generic Class I and II medical devices from the 510(k) process. If you have a generic Class II medical device, you can discover whether it is exempt from a 510(k) filing by searching the FDA Product Classification database.
RELATED READING: 5 Reasons Overhauling FDA 510(k) is a Great Move.
The FDA defines Class III devices as products which “usually sustain or support life, are implanted or present a potential unreasonable risk of illness or injury."
Just 10 percent of the devices regulated by the US FDA fall into Class III. This classification is generally extended to permanent implants, smart medical devices, and life support systems.
While Class III is generally reserved for the most innovative and cutting-edge medical devices, there are other devices which can fall into Class III for different reasons. Some devices which are categorized initially as Class II may be bumped up to Class III if the manufacturer is unable to demonstrate substantial equivalence to a predicate (existing product) during the PMA (510k) filing process.
Examples of Class III Medical Devices:
- Breast implants
- High-frequency ventilators
- Cochlear implants
- Fetal blood sampling monitors
- Implanted prosthetics
Class III devices are subject to all FDA General Controls and the FDA Premarket Approval (PMA) process. The FDA writes, "due to the level of risk associated with Class III devices, FDA has determined that general and special controls alone are insufficient to assure the safety and effectiveness of Class III devices."
The PMA is the most intensive type of device marketing application required by the FDA. Some FDA Class III devices are exempt and may qualify for a 510(k) filing, but the majority are expected to gain Premarket approval.
The PMA process requires a rigorous study of a medical device to prove safety and effectiveness through the development of a data-driven benefit/risk profile. The PMA process generally involves clinical trials and significant time and resources for sufficient data collection. The only exceptions to the PMA process within Class III are devices with a substantial equivalent. You can determine whether a Class III device can be marketed with a 510(k) by searching the FDA Premarket Approval (PMA) database and the 510(k) Premarket Notification database.
How to Determine Your Class
The first step towards classifying your Medical Device is to navigate the FDA Classification regulations, the list of 16 categories for medical devices according to medical specialization.
As an example, we'll show you the steps to identify the classification of a blood pressure alarm. The device is classified under category 870: Cardiovascular devices.
Once you've located the relevant medical specialty, click on the category, and navigate the list of devices until you find an equivalent and the associated device code.
Click on the device code and open the guidelines. The device classification is listed under section (b).
If your device lacks a listed equivalent among the 1,700 devices classified by the FDA, it is most likely an innovative device without a substantial equivalent and would be classified as Class III.
Understanding FDA Medical Device Classes
The differences between medical devices classified as Class I, II, or III by the FDA is mostly risk, amount of contact with a patient and their internal systems, and whether a device is critical to sustaining life.
In addition to these factors, the FDA considers substantial equivalence when determining how a device is classified. If your device is low-risk and minimally contacts the patient, you are likely to qualify for Class I and a streamlined market approval process. Class II and III devices must demonstrate safety via substantive equivalence, a 510(k) filing, or the premarket approval process.
By knowing how your device is classified, you can streamline your path to market approval by understanding the processes and documents which are likely to be required by the FDA. If your organization is subject to a Class II or Class III 510(k) or PMA requirement, this knowledge can help you allocate the appropriate resources in advance and plan for a successful filing.