Are Lab-Equivalent Results Required for Point of Care Testing?
Best practices for evaluating the design trade-offs that may need to be made to achieve acceptable levels of accuracy, sensitivity, cost, and time to result and best match the needs for a particular test.
The future of in vitro diagnostics (IVD) is rapid, precise, and efficient solutions. While the traditional model—samples analyzed by skilled technologists using large, complex instrumentation—is not going away in the lab of the future, the central lab is increasingly complemented by decentralized testing at the point of care.
In the past 20 years, the menu of available Point of Care (POC) tests has grown more than tenfold, to over 110 different assays1, and the first molecular POC test received CLIA waived status in 2015.
Patients can receive life-saving, time sensitive tests in decentralized locations.
Home testing is now available with auto-reporting via mobile phone.
Targeted testing for public health pathogens is available in remote locations where reaching a lab is impossible.
However, for Point of Care diagnostic systems to be viable in these testing scenarios, manufacturers need to determine if lab-equivalent results are required. This includes evaluating the design trade-offs that may need to be made to achieve acceptable levels of accuracy, sensitivity, cost, and time to result and best match the needs for a particular test. When making these important decisions, the product development team must carefully consider the clinical requirements, practical use cases, as well as acceptable levels of variability in results.
Below are some of the best practices Invetech employs with our clients to help evaluate the challenging trade-off decisions that can define competitive advantage and help to achieve market-leading products.
Is Point of Care the right solution?
In the early stages of a project, it is important to articulate why you’re designing a Point of Care diagnostic solution with a business case—what problem is being solved, who will perform the test, how will the results will be used, and so on. Defining the most important features of the product early on will help you evaluate the important decisions that must be made in the instrument and cartridge design.
As an example, some tests are targeted to critical settings where standard lab tests aren’t practical. In those instances—such as ER cardiac marker testing to determine time sensitive interventional therapy—tests are required to be both accurate and sensitive, comparable to lab testing.
Other tests are developed to be cost-effective for private in-home testing—such as rapid HIV tests where patients will receive a confirmatory lab test prior to treatment. In those scenarios, the product development team might weight affordability and ease of use more heavily and accept lower accuracy of results.
For many of our original equipment manufacture (OEM) clients, the decision to develop a system for point of care is driven by the intended application in that market. The OEM may be willing to accept lower performance to achieve more immediate results. Alternatively, the requirement for lab-equivalent results from a POCT system may require the design to provide solutions that deliver the required test accuracy and sensitivity. The business case for the new test will include these performance factors, as well as considerations for development, final system cost and time to market.
Define clinical requirements to determine critical design features and performance specifications
While it might seem intuitive to expect new Point of Care diagnostic systems to deliver state-of-the-art test results, equivalent performance to central lab results may not always be required for informing reliable clinical decisions at the point of care.
To evaluate this equivalent results paradigm, product developers should consult clinicians and other healthcare stakeholders to understand the results required to make actionable clinical decisions. Together the product design team and healthcare stakeholders should consider how the results will be used, the benefits that will arise from POCT, and the performance requirements for the POCT application. That information should be used to define the product requirements—ensuring the Point of Care diagnostic system will meet minimum performance for reliability, accuracy, and ease of use—and drive decisions regarding the critical features for the device and the performance specifications required by the intended users and markets.
Understand which trade-offs are acceptable for the POCT system
After you create the guidelines for product design based on the clinical requirements, your team should collaborate with key stakeholders to determine the non-negotiable features of the system for your specific use case. This should include discussing the practical use cases until the product design, performance requirements and specifications are aligned.
Some important design questions for this process include:
What are the sample collection requirements? Are they feasible for point of care?
What are the design and production constraints around the instrument and cartridge dimensions, system durability and performance? Are there additional design options to improve performance reliability and cost per test?
What user experience (UX) and human factors engineering (HFE) elements need to be considered to meet the needs for the intended user? How can errors be reduced through clear directions for use or other methods?
Will the test be followed up by a lab test, and is the condition we’re testing for life-threatening?
Is test cost prohibitive to test adoption? Are we willing to reduce accuracy or sensitivity to lower costs and potentially reach more people who will benefit from the test?
Is time to result one of the critical factors for the test, and how much faster is required to justify implementing a Point of Care test?
As an example, a Point of Care blood test can be administered using blood draw or a finger prick. Because it can be impractical to draw blood in a point of care setting, the requirements may include designing a microfluidic cartridge and test process that provides the needed sensitivity from a smaller blood sample—the finger prick. Although the finger prick blood sample is a non-negotiable requirement for many POCT applications, this sample collection method can introduce significant variability in test results. However, a key benefit for the Point of Care test might be time to result, not sample collection technique. Therefore, if providing a clinical diagnosis and treatment decision during a single health provider visit so the patient can receive immediate action to address the health concern, the product design team might choose to allow somewhat more variability in test sensitivity to enable faster time to result.
Define the product specifications
Once your product development team has carefully considered the clinical requirements, practical use cases, and acceptable trade-offs for the POCT system—these requirements need to be translated into product specifications and critical design parameters. When doing so, there are four primary and interrelated requirements that will directly impact POCT results:
Achieving accurate and sensitive results that can be used to make clinical decisions
In a short time frame that enables rapid initiation of appropriate treatment
Without risk of error introduced by minimally trained operators
At a price point—instrument and cartridge—that provides value to the healthcare system
To ensure holistic system design is focused on these important Point of Care diagnostic product requirements, the critical design parameters must be clearly understood and identified. This approach allows the team to quickly focus on systematic problem-solving for the mission critical design challenges that are revealed through this process.
White Paper: Best Practices for Point of Care Product Development
In this white paper, we discuss best practices and proven approaches for POC product development, and provide context for making the hard trade-off decisions that can define competitive advantage and help to achieve market-leading products.