What Counts as SaMD? FDA Definition in Plain English
- Beng Ee Lim
- May 7
- 4 min read
TL;DR: SaMD (Software as a Medical Device) is standalone software that:
Uses medical data
Makes a medical claim
Works independently of a physical device
If your software does all three: ✅ it’s likely SaMD.
So, What Does “SaMD” Actually Mean?
SaMD stands for Software as a Medical Device. But what does that actually mean in plain English—not legal jargon? Let’s break it down.
FDA’s Formal Definition
According to the FDA, SaMD is software intended to be used for one or more medical purposes—without being part of a hardware medical device.
IMDRF’s Global Framework
The IMDRF (International Medical Device Regulators Forum) shaped the global thinking on SaMD. It introduced four risk categories, from Class I (low risk) to Class IV (high risk), based on how much potential harm could occur if the software failed. The FDA now aligns with this framework in many cases.
The 3-Step Litmus Test to Know If You’ve Got a SaMD
Here’s a simple test you can run to figure out if your software counts as SaMD.
Step 1: Does your software use medical data?
Think blood pressure, blood glucose, imaging data, heart rate—anything clinically relevant.
Step 2: Does it make a medical claim?
This includes diagnosis, screening, monitoring, or treatment guidance. Even if it just supports doctors with decisions, that’s a medical claim.
Step 3: Does it work independently of a device?
If it runs on a smartphone, in the cloud, or a laptop—without being embedded in or dependent on a specific device—it’s standalone.
Quick Decision Matrix:
Uses medical data | Makes medical claim | Stand‑alone software | Likely SaMD? |
✅ | ✅ | ✅ | Yes |
✅ | ✅ | ❌ | Part of the device, not SaMD |
✅ | ❌ | ✅ | Often wellness / CDS* |
❌ | ❌ | ✅ | Unregulated wellness |
If you answered “yes” to all three, your software is probably SaMD.
What About Edge Cases?
There are some gray zones—here’s what you need to know.
Clinical Decision Support (CDS)
If your tool just presents guidelines or raw data, you’re probably safe. But if it goes a step further—interpreting, flagging, recommending treatment—then the FDA may consider it SaMD.
Wellness Apps
Sleep trackers, step counters, meditation apps—these are usually not SaMD. But if they claim to treat anxiety, improve heart health, or diagnose sleep apnea? Now we’re in SaMD territory.
Firmware vs. SaMD vs. Device Software
This one trips a lot of people up.
Firmware (software embedded in a device) is not SaMD.
Software that controls a specific device (like an insulin pump app) is also not SaMD—it’s part of the device.
But standalone software analyzing data (like an AI tool for X-rays)? That’s SaMD.
Scenario | SaMD? | Why |
Clinical Decision Support (CDS) that only shows guidelines | Usually No | Presents data without interpreting |
CDS that flags high‑risk patients | Often Yes | Interprets & recommends action |
Wellness app tracking sleep & steps | No | General wellness claim |
Wellness app claiming to treat insomnia | Yes | Medical claim triggers SaMD |
Firmware inside an insulin pump | No | Embedded → part of the device |
Cloud AI that analyses X‑rays | Yes | Stand‑alone, medical claim |
“In 2025, the FDA clarified that many standalone apps previously flying under the radar now fall under SaMD—especially those using AI or clinical imaging.”
Real-World SaMD Examples
Let’s put this into practice.
Example 1: Blood-Glucose Monitoring App
It uses data from a sensor, analyzes trends, and alerts the user about high or low glucose.
✔ Medical data
✔ Medical claim
✔ Works independently of a device
➡ This is SaMD.
Example 2: Sleep Tracker
It tracks sleep cycles and gives you a “sleep score.”
✘ No medical claim
✘ General wellness only
➡ This is not SaMD.
Want a Fast Answer?
You can check your SaMD status instantly. Use Complizen’s free tool—just answer 3 questions and get your answer in seconds.
3 Common Misconceptions About SaMD
“If it’s not running on a medical device, it’s not regulated.”
Wrong. In fact, SaMD is defined because it runs on general-use platforms—like phones or laptops.
“Wellness apps don’t need to worry about the FDA.”
Not true. The line between wellness and medical is blurry. If your app promises medical outcomes, you’re in FDA territory.
“If it’s only for doctors, it’s not SaMD.”
Not quite. Physician-facing software is still regulated if it supports diagnosis or treatment.
Conclusion: Know What You’re Building
You don’t need to be a regulatory expert—but you do need to know whether the FDA cares about your software.
SaMD is about what your software does, not how you build it.
If it handles medical data, makes a medical claim, and works independently, it probably counts.
Don’t guess. Use the free checker and move forward with confidence.
A few minutes now can save you months down the road.
FAQs
What is a “device software function”?
It’s any software feature that serves a medical purpose—like analyzing, interpreting, or treating health-related data.
Can software be both SaMD and part of a device?
No. If it requires a specific device to function, it’s considered part of the device, not standalone SaMD.
What are IMDRF SaMD risk categories?
They classify SaMD from Class I (lowest risk) to Class IV (highest risk), depending on the severity of harm if the software fails.
Is every health app a SaMD?
Nope. Most aren’t—unless they cross the line into diagnosing, treating, or guiding medical care.
What if my software connects to a wearable device?
It depends. If the software relies on the wearable to function, it’s part of the system—not standalone SaMD. But it still may be regulated.
