Software as a Medical Device (SaMD)
Software as a Medical Device (SaMD) is software intended for one or more medical purposes that performs them without being part of a hardware medical device (the IMDRF definition).
Reviewed by Peleg Chevion, Managing Partner
The International Medical Device Regulators Forum (IMDRF) set it, and FDA describes SaMD as one of three types of software related to medical devices, the others being software integral to a device and software used to manufacture or maintain one.
Mechanism
Section 201(h)(1) of the Federal Food, Drug, and Cosmetic Act (FD&C Act) defines a device by its intended use in diagnosing, curing, mitigating, treating or preventing disease, and that definition excludes software functions carved out under section 520(o). Section 3060(a) of the 21st Century Cures Act, enacted December 13, 2016, added section 520(o).
Clinical decision support (CDS) software is excluded only if it meets the four criteria FDA draws from section 520(o)(1)(E), its lead-in and clauses (i) through (iii): it does not analyze a medical image, an in vitro diagnostic signal or a signal-acquisition pattern; it displays, analyzes or prints medical information; it supports or provides recommendations to a health care professional; and it lets that professional independently review the basis for each recommendation.
FDA reissued its guidance on January 29, 2026, superseding a January 6, 2026 version. It states that where only one option is clinically appropriate and the function otherwise meets all the criteria, FDA does not intend to enforce FD&C Act requirements. It states that software recommending to patients or caregivers meets the device definition, and that functions for critical, time-sensitive decisions do not meet the fourth criterion.
The IMDRF risk framework (N12, September 18, 2014) sorts SaMD into Categories I through IV by combining the significance of the information to the healthcare decision with the state of the healthcare situation, and Category IV carries the highest impact. The IMDRF clinical evaluation document (N41, September 21, 2017) organizes the evidence into valid clinical association, analytical validation and clinical validation.
FDA authorizes a device through one of three routes. Under section 513(f)(1), a device not marketed before May 28, 1976 is class III by default, and the exceptions include substantial equivalence to a device within a classified type and classification through a De Novo request. A 510(k) succeeds when FDA issues an order declaring the device substantially equivalent to a legally marketed predicate (21 CFR 807.100(a)(1)). A De Novo request serves a device with no legally marketed device on which to base substantial equivalence (21 CFR 860.200). A premarket approval application (PMA) governs class III devices under 21 CFR Part 814.
Congress created the Breakthrough Devices Program (section 515B) for devices offering more effective treatment or diagnosis of life-threatening or irreversibly debilitating conditions that also meet one further statutory test. FDA reports 1,320 designations granted and 210 marketing authorizations for designated devices as of June 30, 2026.
A predetermined change control plan (PCCP) lets a manufacturer pre-authorize future modifications under section 515C of the FD&C Act, added by the Food and Drug Omnibus Reform Act of 2022. FDA's guidance for AI-enabled device software functions was issued December 4, 2024 and reissued August 18, 2025. FDA's guidance on PCCPs for devices generally, issued August 22, 2024, and the January 2025 AI lifecycle guidance remain drafts on FDA's site.
Worked Example
A count of the entries on FDA's list of AI-enabled medical devices, current as of September 4, 2026, gives 1,614 entries: 1,553 cleared through 510(k), 40 granted through De Novo and 21 approved under PMA. The shares are 96.2, 2.5 and 1.3 percent (1,553, 40 and 21, each divided by 1,614). FDA states that the list is not a comprehensive resource of AI-enabled devices.
Three hypothetical functions illustrate the tests. First, a tool that shows a physician a guideline-based dosing recommendation, with its basis visible, can satisfy all four criteria and fall outside the device definition. Second, a tool that detects nodules on computed tomography images fails the first criterion because it analyzes a medical image, so it is a device. Third, an application that sends treatment recommendations to patients is a device under FDA's guidance.
What It Means for a Limited Partner
For an allocator, the regulatory route is an underwriting variable that sets the cost, the timing and the evidence a company must produce. A function excluded under section 520(o) sits outside device premarket review, while a function that is a device must carry premarket evidence through a 510(k), De Novo request or PMA. The 510(k) route accounts for most of the entries on FDA's list.
Three diligence questions follow. Does the labeled intended use fall inside or outside section 520(o)? Which route does the company need? Does a PCCP let the model change after authorization without a new submission for each modification? Section 515C provides that a PMA supplement or new 510(k) is not required for a change consistent with a plan FDA approved or cleared.
In Life Sciences and Healthcare
Authorization is not coverage. The Centers for Medicare & Medicaid Services created Transitional Coverage for Emerging Technologies (TCET), a voluntary pathway for certain FDA-designated Breakthrough Devices within a Medicare benefit category, with a goal of finalizing a national coverage determination within six months after FDA authorization. Software that analyzes a signal from an in vitro diagnostic device cannot use the CDS exclusion, because the lead-in to section 520(o)(1)(E) excludes it, so it is regulated as a device. Coverage is separate: absent a national coverage policy, CMS states that Medicare contractors may cover an item or service based on a local coverage determination.
Governing Authority and Sources
- FD&C Act sections 201(h), 520(o), 513(f) and 515B.
- 21 CFR Part 807 Subpart E, Part 814 and Part 860 Subpart D.
- FDA, Clinical Decision Support Software (January 29, 2026) and Software as a Medical Device.
- IMDRF, Key Definitions (N10, 2013), Risk Categorization Framework (N12, 2014) and Clinical Evaluation (N41, 2017).
- FDA, PCCP for AI-enabled device software functions (August 18, 2025).
- CMS, TCET final notice (CMS-3421-FN).
Frequently Asked Questions
What is a Breakthrough Device designation?
It is a voluntary FDA designation for devices that provide more effective treatment or diagnosis of life-threatening or irreversibly debilitating conditions and meet one further test, such as having no approved or cleared alternative. A sponsor may request it before submitting a PMA, 510(k) or De Novo request, and FDA decides within 60 calendar days under section 515B.
What is the difference between 510(k) and PMA?
A 510(k) clears a device by showing substantial equivalence to a legally marketed predicate, while a PMA approves a class III device under 21 CFR Part 814. Counting the entries on FDA's AI-enabled device list, current as of September 4, 2026, 1,553 of 1,614 are 510(k) clearances and 21 are PMA entries; FDA states the list is not comprehensive.
What is the De Novo pathway?
De Novo is the route to class I or class II classification for a device with no legally marketed device on which to base substantial equivalence, under 21 CFR Part 860 Subpart D. A requester may file it after a not substantially equivalent 510(k) determination or directly, and the same count of FDA's AI-enabled device list finds 40 of its 1,614 entries through that route.
Related Reference
Pillar: Diagnostics and Precision Medicine.