510(k) vs. PMA: How Cybersecurity Testing Requirements Differ

Medical device manufacturers preparing for FDA submission often ask us the same question: "Does the cybersecurity testing requirement change depending on whether we're filing a 510(k) or a PMA?"

The short answer is yes — but not in the way most people expect. The FDA's premarket cybersecurity guidance applies to both pathways, but the depth of scrutiny and the documentation burden differ significantly.

The Basics

510(k) — You're claiming your device is substantially equivalent to a legally marketed predicate device. This is the pathway for most Class II devices (moderate risk). The review is faster and the documentation requirements are lighter than PMA.

PMA (Premarket Approval) — Required for Class III devices (high risk) due to the level of risk they pose to patients. This is the most rigorous review pathway, requiring clinical evidence and extensive technical documentation — regardless of whether a predicate device exists.

Both pathways now require cybersecurity documentation under Section 524B of the FD&C Act. The difference is in how deeply the FDA scrutinizes that documentation.

Cybersecurity Requirements: What's the Same

Regardless of submission pathway, the FDA expects:

• Threat modeling using a recognized methodology (STRIDE, TARA, attack trees)
• A Software Bill of Materials (SBOM) listing all software components
• Penetration testing results from an independent third party
• Documentation of security controls — authentication, encryption, access control, secure update mechanisms
• A post-market cybersecurity plan — coordinated vulnerability disclosure, patch management, monitoring
• Clinical risk assessment — how cybersecurity vulnerabilities could affect patient safety

These are table stakes for any connected device, regardless of classification.

Where 510(k) and PMA Diverge

Depth of Threat Modeling

510(k): The FDA expects a threat model that covers your device's attack surfaces and demonstrates you've considered relevant threats. For devices that are substantially equivalent to a well-understood predicate, the threat model can reference known risks from the predicate device class and focus on what's different about your implementation.

PMA: The threat model needs to be comprehensive and device-specific. There's no predicate to reference, so you're building the risk profile from scratch. The FDA will scrutinize every assumption — what threat actors were considered, what attack vectors were analyzed, and how risk ratings were assigned. Expect questions.

Penetration Testing Scope

510(k): Penetration testing should cover all interfaces (network, wireless, firmware, physical, cloud), but the depth of testing can be proportional to the device's risk profile. A Class II patient monitor needs thorough testing, but the FDA may accept a more focused scope than they would for a Class III device.

PMA: Expect the FDA to require exhaustive testing across every attack surface. If your device has BLE, Wi-Fi, a cloud backend, a companion app, and physical interfaces — all of them need to be tested in depth. The review team will look for gaps in your testing scope and ask about anything that wasn't covered.

Equivalency Claims

510(k): If your predicate device had cybersecurity testing performed, you may be able to reference it — but only for components that are truly equivalent. If you changed the wireless protocol, added cloud connectivity, or modified the authentication mechanism, those changes need new testing. The FDA won't accept "our predicate passed, so we're fine" for features that differ.

PMA: There's no equivalency shortcut. Everything needs to be tested and documented from scratch.

Documentation Volume

510(k): Your cybersecurity documentation is typically a dedicated section within the 510(k) submission. It should be thorough but can be concise — focused on demonstrating that you've addressed the key areas.

PMA: The cybersecurity documentation for a PMA can be hundreds of pages. The FDA expects detailed descriptions of your security architecture, threat model, test results, risk mitigations, residual risk analysis, and post-market plans. Every claim needs supporting evidence.

Review Timeline

510(k): Cybersecurity review is part of the overall 510(k) review, which typically takes 3-6 months. If you get an ANIN letter for cybersecurity deficiencies, add 2-4 months.

PMA: The review is longer to begin with (6-12 months), and cybersecurity issues can extend it significantly. PMA reviewers are generally more detailed in their cybersecurity questions, and the back-and-forth can add months if your initial documentation was thin.

What This Means for Your Testing Strategy

If you're filing a 510(k):

• Start with a clear understanding of your predicate device's cybersecurity posture
• Focus your testing on what's new or different from the predicate
• Document equivalency claims clearly — what's the same, what changed, and why the changes don't introduce new risks
• Budget 4 weeks for penetration testing and factor in remediation time before submission

If you're filing a PMA:

• Plan for a more comprehensive engagement — threat modeling followed by full-scope penetration testing
• Start early. PMA cybersecurity documentation takes months to prepare properly
• Budget for the possibility of FDA questions and additional testing rounds
• Consider engaging your pentest firm during the design phase, not just before submission

The Cost Difference

Because PMA requires more extensive documentation and testing, the cybersecurity portion of a PMA submission typically costs more than a 510(k). But the real cost difference isn't in the testing — it's in the rework. A thin 510(k) cybersecurity submission that triggers an ANIN letter costs more in the long run than doing it right the first time. And a PMA that enters multiple rounds of FDA questions can delay market entry by a year or more.

Invest in thorough cybersecurity testing and documentation upfront, regardless of your submission pathway.