Design Reviews: When and How Many?

How often do you need a design review and how many do you need to do? It depends. David Amor

August 22, 2015

6 Min Read
Design Reviews: When and How Many?

When it comes to design reviews, the key is having a defensible, justifiable position that is well documented within your design and development process.

David Amor

Two of the most common questions I get asked in my consulting practice are about design reviews: When are they needed and how many should be done? In typical consultant fashion, I’m going to answer with, “It depends.” However, I’m also going to share some recommendations that may help get you to a defensible answer, which in fact is the main thing you’ll need in front of a regulator.

Let’s start with the most important consideration: There is no regulation or standard that mandates when and how many design reviews to perform.

Design review occurrence and frequency are left to the discretion of the manufacturer. Per 21 CFR 820.30(e) Design Reviews:

“formal documented reviews of the design results are planned and conducted at appropriate stages of the device's design development”

But guess what: “Appropriate” is never defined.

EN ISO 13485 similarly indicates that

“[…]at suitable stages, systematic reviews of design and development shall be performed in accordance with planned arrangements (see 7.3.1).”

You guessed it: “Suitable” is also never defined.

And trust me, I read guidance documents and published guidelines like its my job (because… it is) and have never come across any formal requirement for number and y types of design reviews. Even GHTF/ IMDRF “Guidance On Quality Systems For The Design And Manufacture Of Medical Devices” and FDA’s own “Design Controls Guidance for Medical Manufacturers (2007)” only loosely address these topics.

Now that it has been established that no regulation, standard, or guidance will dictate a hard number and type of design review to hold, here is my personal checklist for solving the design review equation. (Note: there can be exceptions to all of these guidances.)

How Large and Complex Is Your Medical Device Company?

Per 21 CFR 820, the quality management system implemented by your company should reflect its size and complexity. This can be extrapolated to design controls and subsequently to design reviews; thus, it can be reasonably assumed that the larger and more complex your company is, the more design reviews you should potentially have.

How 'Risky' Is Your Device?

Risk-based approaches to medical device scaling decisions are always the safest bet when it comes to deciding things. In that same vein, a higher risk classification device (Class III, Class IIa/IIb in EU) may require more evaluation time points along the development pathway (i.e., design reviews) to ensure the device is safe and effective and conforms to the specified design inputs. I would expect, for example, that a toothbrush manufacturer’s design reviews may be less frequent and in depth when compared with those of a company that designs pacemakers.

How Complicated Is Your Device?

More complex devices may require a systems engineering approach to development which necessitates more frequency meetings to ensure that all interfaces and development partners are aligned and that the overall product’s design is adequate for its intended use. In a complex electromechanical device project like an infusion pump, more design reviews are most likely necessary to ensure that all subsystems and teams are tracking towards the same goal.

Consider the Following Time Points for Design Reviews

Please note that this list is not exhaustive and could be different for different companies.

Design inputs review. Have user needs been identified? Have user needs been properly translated into technical requirements? Are the design inputs thorough and adequate for the type, complexity and risk of product being developed? Has the concept or prototype been fully characterized with design inputs? Are all of the design inputs unambiguous, verifiable, and easy to understand? Outcome: design inputs are appropriate and fully define the product and its intended use.

After design outputs are established. Do design outputs demonstrate conformance to the design inputs? Do all of the design outputs have acceptance criteria consistent with the design input requirements? Has design for manufacturability been considered? Has a Device Master Record been initiated? Outcome: traceability to design inputs is confirmed.

Predesign verification. Are we ready for design verification? Have we validated processes or are sufficient inspections in place? Is the risk management file underway and are we verifying mitigations for potential risks? Are the test samples product equivalents and the number statistically significant? Have we developed test methods and validated them? Outcome: readiness for design verification.

Postdesign verification. Did we see any failure in design verification? Have we performed root cause analysis? Does our risk management file need to be updated? Do we need consider a design change? Outcome: readiness for design validation.

Design transfer. Is our bill of materials complete? Are all components and materials and assemblies released to production? Did we get acceptable design validation results? Is our DMR complete? Outcome: design is ready to transfer to manufacturing.

The most important considerations when answering when and how many in regards to design reviews is to have a defensible, justifiable position that is well documented within your design and development process. The number of design reviews can fluctuate dependent on a variety of factors, including the ones mentioned in this article, and the quality management system should be flexible enough to allow for this type of approach.

David Amor, MSBE, CQA, is a medtech/biotech consultant and mobile health entrepreneur who founded Medgineering, a company focused on remote compliance, regulatory, and quality systems consulting for larger companies and start-ups alike. Reach him at [email protected].


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