The Evolution of Medical Device Classifications


The Food and Drug Administration (FDA) began regulating medical devices in 1976, when U.S. President Gerald Ford signed into law the Medical Device Amendments Act (MDAA) to the Federal Food, Drug, and Cosmetic Act of 1938. From those amendments, the FDA wrote proposed rules to ensure medical devices were compliant with the MDAA. The body of finalized rules was promulgated in 21 CFR Parts 800-1299. That federal code ushered in the FDA’s classifications of medical devices based on the level of risk to end users: Class I, II, and III.

While the foundation for each level of classification has remained in place, the 1976 Amendments set off a complex regulatory and legislative evolution. It took years for the FDA to develop and finalize the rules necessary to comply with the law. Despite many FDA classification panels and public meetings at work during that period, many devices had gone to market unreviewed.


The winding pathway was redirected with the Safe Medical Devices Act of 1990 (SMDA). The SMDA required the FDA to review and classify the medical devices that had been missed during the years between the amendments and final rules. The SMDA also improved post-market surveillance for permanently implanted medical devices, enabled FDA recalls, and defined the 510k program for devices pursuing classification by substantial equivalence (a new device modified from a previously approved device). The SMDA presented a formidable volume of retroactive work that resulted in languishing progress for the overall classification program.

Facing hampered implementation even as medical device innovation accelerated, the 1997 enactment of the Food and Drug Administration Modernization Act (FDAMA) aimed to reduce hindrances to the classification process. The Act created the DeNovo program to reduce automatic Class III determinations for novel medical devices that had been deemed “not substantially equivalent” using other means. The FDAMA also brought much needed flexibility for the FDA to reassign eligible Class III devices as Class II, using the “least burdensome” requirements and “special controls” instead of classifying solely on existing performance standards. The more than 26,000 total FDA-registered medical devices (13,000 of U.S. origin) show the magnitude of the burden. It is clear why ongoing monitoring between industry and regulatory agencies is crucial to industry at both regional and global levels.

The FDA’s Medical Device Classifications

While familiar content to industry professionals, this is where we currently stand in categorizing medical device risk levels:

Class I (low to moderate risk). Non-invasive, not used to support (or sustain) life—like stethoscopes, tongue depressors, or manual wheelchairs. Representing nearly half of the medical device market, Class I devices are subject to the fewest regulations. Most Class I devices are exempt from premarket notification and premarket approval requirements.

Class II (moderate to high risk). These medical devices can be invasive, or involve sustained direct contact with the human body, such as dissolving sutures, syringes, or catheters. FDA “general controls” are not considered adequate for approving Class II devices. There is no one-size-fits-all criteria list for a device, but FDA requirements for Class II approvals may include performance qualifications, special labeling requirements or post-market surveillance, among others. In many Class II devices, a 510(k) premarket notification application demonstrating safety and effectiveness is required. That said, there are hundreds of more general Class II medical devices that the FDA has listed as exempt from the 510(k).

Class III (high risk). Only around 10 percent of medical devices qualify as Class III. By definition, the FDA states that Class III medical devices “sustain or support life, are implanted at a potential unreasonable risk of illness or injury.” Complex innovations such as defibrillators, Cochlear implants, or high-frequency ventilators are examples of Class III devices.

Global Medical Device Classifications

In other regulatory jurisdictions, medical device classifications have similarities, but currently operate independently and present just as many differences. The FDA’s Class I, Class II or Class III match China’s Class I, II and III nomenclature, yet criteria are not aligned. Canada adds a Class IV. Europe classifies medical devices in another cadence, with Class I, IIa, IIb, and III, and India uses labels Class A, B, C, and D. That is just a sampling of regulatory classifications, without delving into the multitude of unique definitions and requirements that makers must be aware of.

What Lies Ahead

It is hard to predict the future. Yet, there are clear markers that serve as accurate predictors. The rapid development of “smart” and “miniaturized” devices are examples of medical device innovations that could present new classification considerations. Another is global harmonization efforts. Already, harmonization has increased standardization among regulatory bodies. Could medical device classification standardization be next? In 2019, the World Health Organization announced the creation of the “International Classification of Medical Devices (ICMD)” project. The initiative called for industry and regulatory bodies to prioritize harmonization efforts of global medical device classifications and nomenclature. There is always another new opportunity ahead. And we will use our collective expertise and vision to make the most of each concept for the betterment of human health.

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