For teams developing next-generation diagnostic products, many of the core challenges are familiar: balancing analytical performance, robustness, usability, cost, manufacturability, and regulatory requirements. Success lies in making the right trade-offs at the right time, while maintaining momentum and reducing technical risk.
The twelve considerations below are drawn from our experience supporting the development of a wide range of marketed point of care diagnostic systems. Together, they highlight practical principles that help teams establish strong foundations, make informed decisions, and navigate development more effectively. Addressing these areas early can improve development efficiency, reduce costly redesigns, and increase the likelihood of delivering a commercially successful product.
1. Think about cartridge price at the start
The production cost of your cartridge is paramount to the success of your business. Profitability requires a focussed consideration from day one. This includes thinking about cost of materials, simplicity and manufacturing yield, driven by well-engineered forgiving tolerances and where possible, reduced use of expensive materials and reagents.
2. Have a cross functional team
The design of a POCT system is complex and ultimately a series of trade-offs between cost, size, weight, aesthetics, usability and many other aspects. Involving all disciplines in your team, and avoiding silos, helps to ensure that these compromises are well judged and give you a world-class design.
3. Develop your assay ahead of the hardware
Building a system on shaky foundations is something that you’ll live to regret. That’s why it is worth developing your assay as a matter of priority ahead of the hardware. The workflow might not be fully defined, but it does need to be stable enough to allow the cartridge design to proceed without the risk of costly redesign later.
4. Set clear and well-defined requirements
A clear and well thought-through list of requirements will save you countless discussions, misunderstandings and costly design changes. Requirements should be as concise and testable with simple acceptance criteria.
5. Start with the workflow, then the cartridge, then the instrument
The assay workflow in the cartridge is the most important part of the system. Not only does it have to function correctly, but it also needs to meet the constraints of cost, size and usability. Start with the workflow, then the cartridge, and then the instrument. If you approach these in reverse order, you might end up with an ugly and costly mess.
6. De-risk as often as possible
Even at the concept level, risks need to be assessed. When issues occur with prototypes, it is critical that you investigate to establish the root cause. If the answer you’re hearing is "we’ll fix it in software" or "it’ll be alright in production", then you should start to worry!
7. Avoid complex solutions
Complex designs often emerge when teams try to solve every problem with additional features, mechanisms or controls. In our experience, the most successful point of care systems achieve their performance targets with the simplest architecture that can reliably deliver the required workflow. Simpler systems are generally easier to manufacture, validate, scale and support throughout their lifecycle.
8. Build several prototype iterations
A prototype is worth a thousand meetings. Prototypes ensure that you learn quickly by failing early, often and cheaply.
9. Start human factors input from the outset
A good user experience is key to making your product stand out from the competition and drive sales. Get user feedback as soon as practicable. If prototypes aren’t available, generate renders or 3D models to show what the end system might look like and how users will interact with it.
10. Allow plenty of time for prototype debugging and testing
This is something we regularly see in ambitious project plans. Our rule of thumb at TTP for a relatively complex fluidic device, is that once you’ve finished building the prototype, you’re roughly 50% of the way to getting it to successfully run a sample-to-answer test.
11. Don’t freeze the system too early
Time pressures can be good, but freezing the design too early often leads to more protracted and costly development programme. Transferring to production before the product is fully characterised and tested means that design changes become convoluted and paperwork heavy. Changing a spring now requires three days of risk analysis, a paperwork trail that resembles Sherlock’s mind palace, not to mention the scrapping of 10,000 springs that the manufacturer just purchased!
12. Engage manufacturing input early
Not all manufacturers take the same approach, which is why involving them early in the design process can pay dividends. Best practice is evolving; for example, not long ago designers would try to minimise the number of types of screws, whereas recent recommendation from a manufacturer was to use many different screw types and heads to help control the torque requirements for different parts of the assembly.
Taken individually, none of these considerations are radical. Taken together, they represent a mindset that prioritises strong foundations, early de-risking, cross-functional collaboration, and disciplined decision-making throughout the development lifecycle.
Point of care diagnostic systems often rely on the successful integration of assays, cartridges, instruments, users, and manufacturing processes. Teams that actively address these twelve areas early are better placed to move forward with confidence, make informed trade-offs, and create a more predictable path from concept to successful product.
Ultimately, getting these fundamentals right does more than reduce risk. It frees R&D teams to focus on what really matters: delivering reliable, usable, manufacturable and commercially successful diagnostic solutions that can make a meaningful impact in real-world healthcare settings.
