In the last post, we helped you figure out how to classify your device’s risk under both FDA and MDR systems. But knowing your risk class is just the beginning.

Now it’s time to ask: What does that risk class actually mean for your startup’s roadmap, budget, and timeline?

In this post, we’ll break down how risk classification affects your required documentation, need for FDA or Notified Body review, clinical trial expectations, and regulatory costs and complexity

This is where theory meets execution—especially if you’re budgeting, building a timeline, or preparing for funding.

What Your Risk Class Triggers (At a Glance)

Let’s break this down in more detail.

MDR: Documentation and Clinical Burden by Risk Class

Technical Documentation Requirements (Annex II & III)

As described in Post #3 of this series, documentation is one of THE distinguishing features of device certification under the MDR – in part as a tool to achieve the goals of harmonization across NBs.  

The documentation requirements for MDR are listed out in Annex II and III; below is a list of what you can expect:

• Device description, design, and manufacturing information

• Labeling and Instructions for Use (IFU)

• General Safety and Performance Requirements (GSPRs) checklist

• Risk management and benefit-risk analysis

• Verification and validation data

• Post-Market Surveillance (PMS) plan

• Periodic Safety Update Reports (PSURs) or PMS Reports

• Clinical Evaluation Plan and Clinical Evaluation Report (CEP and CER)

Even Class I devices, which do not require NB review prior to marketing, require robust documentation.

Clinical Trials

Under the MDR, clinical trials (called clinical investigations) become increasingly important as device risk increases. For Class IIb and Class III devices, clinical trials are typically required to demonstrate safety and performance. Even for some Class IIa devices—particularly Software as a Medical Device (SaMD) tools—clinical trials may be needed if existing clinical data from equivalent products is unavailable or insufficient. If you can’t establish equivalence to a previously certified device, generating new clinical evidence through a trial may be the only way forward. This means startups should prepare early for the possibility of trial planning, especially when developing novel or AI-enabled products.

Notified Body Review, Cost, & Time Impact

All devices that are Class IIa and higher require NB review (and, well, some Class I devices if they involve sterility, reusability, and measurement capabilities).

• Notified Body review typically adds €15,000–€100,000+ depending on the risk class of your device 
• Review timelines vary but can take between 6 to 24+ months, again, depending on the risk class and the complexity of your device

FDA: Requirement Burden by Risk Class and Pathway

For FDA submissions, your requirement burden depends on your risk class and the pathway applicable to your device.  Whether or not you can show substantial equivalence to an existing device (predicate) greatly impacts the regulatory burden required of Class I and Class II devices. .  

Here’s how requirements break down by pathway.

510(k)-Exempt 

Unlike the MDR, where all Class I devices (ok, fine, with the exception of those that are sterile, reusable, or have some measuring function) are exempt from Notified Body review, this is only the case at the FDA for products that have predicates and are so low-risk that the FDA has officially exempted them from the need for review, a.k.a., the 510(k)- Exempt pathway.  In these cases, you do not need to submit an application to the FDA before marketing your product. However, you are still required to comply with General Controls, which include establishment registration, device listing, appropriate labeling, complaint handling, and good manufacturing practices under 21 CFR Part 820.  Clinical trials are not required, and documentation is minimal—though you must maintain internal records in case of inspection.  Some basic SaMD tools may qualify, though AI-enabled devices usually do not.  Note also though, that the FDA has chosen not to enforce its regulatory authority on many Class I devices, which means you can bypass even the General Controls requirement,  

Timeline: Immediate
Estimated cost: Free to $2,000 (mostly for registration and compliance)
Clinical trial required: No

510(k) Notification Pathway

This is the most common pathway for moderate-risk devices that are substantially equivalent to an existing predicate device. To qualify, your product must have the same intended use and similar technological characteristics to a predicate already cleared by the FDA. As more SaMD are “approved,” more predicates are available to base your product on, which is a good thing for startups.

All devices going through 510(k) must meet General Controls, a substantial equivalence rationale comparing your device to the predicate, risk analysis per ISO 14971, bench and software testing, labeling and Instructions for Use, and any evidence required under applicable Special Controls (e.g., specific software documentation, bench testing, labeling requirements, or cybersecurity criteria).

Clinical trials are rarely required, but may be requested if the device introduces novel features or if Special Controls specify clinical data.

Timeline: 3 to 6 months
Estimated cost: Approximately $6,000 (FDA fee only)
Clinical trial required: Rarely
Documentation: General controls, special controls, and substantial equivalence rationale

De Novo Classification (Class I or II with no predicate)

If your device is low- or moderate-risk (yes, even Class I devices) but there is no suitable predicate, you must go through the De Novo pathway. Because you can’t rely on data produced by a predicate device, your submission must independently demonstrate that the device is safe and eff.

Documentation requirements include a detailed benefit-risk analysis, bench and software testing, labeling and marketing materials, clinical data (especially for novel technologies or intended uses), risk management documentation, and proposed post-market controls.

Clinical trials are more commonly required for De Novo submissions than for 510(k), particularly if the product includes AI/ML or performs a new diagnostic or therapeutic function.

Timeline: 6 to 12 months
Estimated cost: Approximately $33,000 (FDA fee only)
Clinical trial required: Sometimes
Documentation: moderate to high

Premarket Approval

The PMA pathway is used for high-risk or implantable devices and is the most resource-intensive FDA route. Devices that are Risk Class III cannot reference predicates (even if there are substantially equivalent devices on the market).  The FDA wants to touch, feel, look into and evaluate thoroughly any device that goes onto the market that could cause serious or fatal injury.  And this is as it should be.  

PMA submissions must include full clinical trial data demonstrating safety and efficacy, extensive documentation of device design and manufacturing, biocompatibility and toxicology reports, and long-term post-market surveillance plans. Some devices are also subject to FDA advisory committee review.

Timeline: 1 to 3 years
Estimated cost: $150,000 or more
Clinical trial required: Yes
Documentation: Intense

Why This Matters for Founders

Your device’s risk class defines your regulatory scope. It sets the boundaries for how far you’ll need to go, how fast you can move, and how much it will cost to get your product to market. For founders, these aren’t just compliance details—they’re strategic constraints that shape your development roadmap, your fundraising goals, and your time to launch.

Take a simple Class II SaMD tool, for example. In the U.S., if it aligns closely with a predicate device, it may qualify for 510(k) status and can launch within a couple months. But that same tool, if pitched with a slightly different intended use may not qualify for 510 (k).  That same product, if introduced in the EU, could fall under MDR Class IIa, triggering Notified Body review and a much more time-consuming, resource-intensive process. If you’re raising funding, planning a multi-market launch, or working with enterprise buyers, these differences are critical to understand early. They’ll affect your messaging, your pitch, and your overall go-to-market strategy.

Your risk class is your regulatory scope. It tells you:

• How far you need to go

• How fast you can get there

• What it’s going to cost to get to market

For example:

• A Class I SaMD tool with a strong predicate may qualify for 510(k)-exempt status and launch in the U.S. within month

• That same tool, if positioned differently or launching in the EU, may be classed as MDR Class IIa, triggering Notified Body review and a much longer, more expensive pathway

If you’re planning to raise funding, launch in multiple markets, or pitch to enterprise buyers, these are critical variables to understand—early.

Takeaways: Best Regulatory Options (in terms of time and money)

• Class I (FDA or MDR): Move fast, but document thoroughly in case of audit

• Class II (FDA): Find a strong predicate early and build your 510(k) strategy

• Class IIa or IIb (MDR): Budget for clinical data and Notified Body time

• Class III (FDA or MDR): Bring in regulatory expertise immediately

Up Next: Which Regulatory Pathway Should You Use?

In the final blog post of this series, we’ll connect your risk class to the actual regulatory pathways available to you and help you pick the right path: 510(k), De Novo, PMA, or MDR NB review

This is the bridge from strategy to action. Don’t miss it.