Creating a new device of any kind can be complex and arduous. But when you add FDA regulation and other approval processes into the mix, the development cycle becomes even more complicated. Medical devices come with unique challenges that can’t be ignored. Anything that pertains to the health and safety of users goes under intense scrutiny and with good reason.

The approval process can take months or years to complete, resulting in added development costs and an unnecessarily long time-to-market period. While there's no getting around regulatory compliance, well-written product requirements can speed the process up significantly.

Medical device product requirements improve the efficiency of a development project, clarifying details across different teams.

What's the Purpose of Writing Product Requirements?

Ultimately, product requirements define a product's purpose, functionality, and features without any uncertainty. It's free of vague language, laying out the exact parameters needed to make the device function as intended. Think of it as a guide that ensures every team is on the same page as you turn a simple idea into a reality.

Clear requirements keep the team working well together, making the design process more efficient and ensuring your submission to the FDA is handled quickly. Well-written requirements take extra time initially, but they avoid delays and cost overruns later in the project.

How Product Requirements Differ for Medical Devices

The product requirements also play a crucial role in testing. Every requirement must be measurable to ensure that the product performs the way it was intended. That applies to any device you make.

However, what makes product requirements different for medical devices is the importance of regulatory compliance. The FDA regulates medical devices to assure their safety and effectiveness of use. You cannot release a medical product without FDA approval unless it is a class I device. Otherwise, you expose your business to hefty fines, penalties, and possible lawsuits.

You will submit documents to the FDA for a 510(k), PMA, or another form of approval. The verification testing checks that each requirement has been met. This is an important part of the Design Control required by the FDA.

Validation refers to customer needs. During the approval application, you must provide evidence that your device fulfills the user's needs and stands up to any claims you make about its capabilities. Typically, validation happens through detailed clinical trials.

Verification is about proper design. It covers aspects like safety, risk management, and overall functionality. Proving effective is no easy task. It involves testing every requirement in a lab. From high-level requirements to more complex sub-systems, it all requires verification. Besides describing the product function, requirements cover risk mitigation. You need to do risk analysis as part of creating the requirements.

That's where the product requirements are critical. They must be written so that each requirement will pass or fail. Any ambiguous requirement will be difficult to verify. If there are missing requirements that have not been verified, your FDA application approval will be slowed.

The need for verification and validation also cements the importance of well-written product requirements. With untestable or conflicting requirements, it's impossible to verify proper implementation. You'd have to go back to the drawing board, spend more time and money investing in complex testing, and waste valuable time.

Carefully writing your product requirements can avoid all of that, ensuring that the approval process continues smoothly.

Writing Comprehensive Product Requirements

Despite the importance of the product requirements, there's no defined way to do things. Project managers typically handle these matters. However, you can have a separate team or a third-party development company take care of the details.

Either way, it's all about finding a method that works for every member of your team while making information as straightforward as possible.

The following are typical steps often used in the process.

1. Gathering Requirements

The first step in the process is to gather the requirements. That might sound easy enough, but it's one of the most challenging steps to get through. Most projects start as simple ideas before evolving into something tangible.

Getting your team from that initial vision to the point where they can make technical decisions requires a significant time investment. You must go beyond high-level descriptions to make detailed requirements that guide the project moving forward.

So, how do you go about gathering requirements?

The best course of action is to brainstorm with team leaders. Go over every expectation and collaborate to pinpoint priority requirements. It's also a great time to expand the idea and develop stretch goals.

Ask questions and create a list of queries for people in different roles. There's a good chance that various players in your company will have a hand in developing the requirements. There might be a software aspect, mechanical elements, electrical details, and more. Having different voices can help uncover overlooked requirements while honing the core functions you need to achieve. It is essential to have input from all stakeholders, including manufacturing, support, and marketing.

The marketing requirements document, or MRD, is another excellent place to look. Developed by the marketing team, this document typically comes before the product requirements phase. It defines your core demographic and outlines what the target user needs are for your product.

The MRD is high-level, but every product should start its life by defining the market. Use this document to develop requirements that fulfill those market needs.

2. Form and Structure

Product requirements are kept in a variety of formats. Some choose simple Word files with hierarchal font systems to indicate importance. Alternatively, some developers employ advanced software and feature-rich databases to track every detail.

Once again, there's no set way to write product requirements. It's up to you and your development team to choose a structure that works best.

All that said, one of the most effective and often used options is a spreadsheet. A spreadsheet keeps all the pertinent data organized and easy to read at a glance. Each individual requirement is in a separate cell, so you can more easily check that each requirement is well written.

Try creating separate columns for:

• Quick-reference ID numbers
• High-level component categories
• Sub-systems
• Requirement sources
• Priority level
• Comments or notes

3. Specifying Product Level Requirements

When writing product requirements for medical devices, you must include information for every possible element. Your submission to regulatory boards will be scrutinized, so you must include comprehensive testing data and evidence where possible.

Specify requirements for:

• Functionality
• Usability
• User and system interfaces
• Environmental impact
• Manufacturing processes
• Serviceability and support
• Alarms and visual annunciators
• Cleaning and sterilization processes
• Performance parameters
• Physical details
• Reliability & Security
• Quality
• Regulatory data
• Safety details
• Packaging details
• Calibration processes
• Disposal procedures
• Compatibility
• Internalization and globalization
• Price and manufacturing costs
• Best Practices

While there are no set standards for writing product requirements, there are several accepted techniques for efficiency. The goal of creating product requirements for medical devices is to gather all the necessary evidence necessary for approvals while streamlining the development process. You can minimize confusion and improve information-sharing across teams. Here are some useful tips.

4. Make All Requirements Testable

Every requirement needs to be testable. This tip might sound obvious, but it's easy to fall back on terms that don't offer measurable action.

For example, stating that an interface must be "user-friendly" doesn't do much. There's no way to measure user-friendliness. As a result, that requirement is untestable. Instead, you can specify several requirements that together make it user-friendly. You may specify the organization of the screen of software or the location of controls.

Consider checking with cross-functional teams to review testability. Multiple perspectives can ensure that you're not creating unmeasurable requirements.

5. Use Quantifiable and Measurable Terms

Quantifiable data is a must. Once again, vagueness will only confuse when developing a product. Numbers don't lie, and there's no room for interpretation. Stick to specifics and create requirements with precise terminology.

6. Avoid Duplicates and Contradictions

Here's another area where cross-functional teams can help spot issues. Regulatory requirements for different agencies can sometimes overlap and contradict one another. You may also encounter situations where one condition forces another to fail.

Review your requirements carefully and consider how they affect one another. Then, have a process for dealing with issues as they arise. Does one condition have priority over another?

Figuring those things out now can save headaches later.

7. Use Imperative Language

Eliminate any doubt of importance by using imperative language. Adopt shall/should terminology to indicate the product's priorities. The word "Shall" reads as non-negotiable, letting your team know that this requirement is not optional. Remove or resolve any “Should” terminology to prevent any design miscommunications within teams, such as hardware or software teams. “Should” is good to have initially, but these should become firm requirements or be removed before doing verification testing.

8. Maintain an Audit Trail

Finally, keep a paper trail for changes and updates. It's easy to get confused with so many team members using the same list of product requirements for guidance. You might end up working from an older version, which will only create delays.

Establish a control system that captures changes and creates an audit trail. That way, you can always go back and make corrections if any issues arise.

Reduce Complexity and Keep Your Project Running Smoothly

Developing a medical device involves a slew of moving parts and many hard-working departments. The one thing that unifies the project is your product requirements. Writing detailed requirements will keep everyone on the same page and prepare your company for the rigors of regulatory approval ahead.

Get more details by reading this Voler Systems guide on creating product requirements for medical devices.

If you need professional assistance creating your medical device's product requirements, turn to Voler Systems. We have many years of experience helping clients develop devices on time and within budget. Our team is familiar with the complexities of medical device development, and we're ready to turn your vision into reality.