COVID-19 Use Settings (Storyboards)

In order to assist test developers and users, Halteres has developed a series of Storyboards, to help envision possible settings and processes for the use of products defined in the Use Cases. Links to the individual Use Setting descriptions are provided to the right. We have discussed the descriptions amongst ourselves for many hours and have modified their content a number of times accordingly. If you are unclear as to why storyboards can be valuable to develop, we invite you to review our discussion of designing products that facilitate actions, particularly the part about Use Settings.

Note that some of the Storyboards describe testing as it is done today, while others show new processes that we suggest could be useful, such as triage testing. In some of these cases there are no appropriately designed or performing tests available at this time, but there are some in development. We hope some of you will take up the gauntlet and develop the tests we propose while others will find these materials important to understand your needs when selecting products and services. We hope you find the Storyboards useful. You may use them as you see fit, but please credit Halteres if you do. We welcome comments and proposed modifications.

Although the illustrations depicting the testing platforms might remind you of specific available platforms, these generic Storyboards are meant to be technology “agnostic”. Nevertheless, based upon the implications of the speed and throughput implied by the workflow, the size and style of the platforms represent the general type we envisioned would be necessary as we prepared the Storyboards. Storyboards that are very similar are shown in the same color in the links on the right. We present very detailed descriptions for only the first of the Storyboards shown in a group, and for the other Storyboards in a group, we focus on describing the differences between it and the other related Storyboards.

Remember that it’s impossible for the storyboards to reflect every aspect of all settings or every possible process variation. However, they should serve as a learning and communication tool that helps guide the development team towards a product that will fulfill needs of the stakeholders in the broader diagnostic ecosystem, as described in our discussion of designing products that facilitate actions. For test users and purchasers, we think you are likely to find a Storyboard that is close enough to depicting your situation to be useful to help you understand when one product is appropriate for Use Cases of interest to you, and when other products are not. In the future, we will link these Use Cases and Storyboards to TPPs.

Throughout the process of constructing the Storyboards, we were forced to consider the implications and nuances of the processes. It also pointed to some of the product design issues that will need to be considered if an adequate test will be provided.

We believe that triage and confirmation testing is a major opportunity that is unmet to our knowledge at the time of this writing (July 2020). In review of Storyboard A and Storyboard B, we conclude that although on-site triage and confirmation testing would be preferred (Storyboard A), off-site confirmation testing (Storyboard B) would be acceptable since it is very much like diagnostics testing off-site (Storyboard C), but would improve the effective use of RNA tests, most of which are negative today. At this time of this writing (July 2020), the highest test positive rate in the US is Arizona at ~27%, however in most states it is <5%. So, a site that collects samples for shipment for off-site RNA testing could be made much more efficient if simple triage tests were available. The number of shipped samples could easily decrease by >10 fold (see Observations and Implications for Storyboard A). Although there is little concern about costs today, with time the decreased cost of triage and confirmation testing versus diagnostics testing will be quite important. Achieving this will require very fast, inexpensive and sensitive triage tests.

The processes for sample collection, transport and testing are very similar in Storyboard B (confirmation testing), Storyboard D (diagnosis), Storyboard F (differential diagnosis) and Storyboard G (surveillance; intended use 1 and 2). This suggests that a single, properly designed laboratory RNA or antigen test could be used in all of these workflows. However, to achieve this it would be necessary to consider the requirements that would be the most difficult to meet across each of these workflows, such as sample type. Nasopharyngeal swabs could be difficult to implement in surveillance studies, whereas saliva or mid-turbinate collection could enable all four workflows. The time-to-results for testing for confirmation or diagnosis is far more important than for surveillance testing. It is possible that a test designed as a SARS-CoV-2 diagnostic test or differential diagnostic test could be used for confirmation testing or surveillance testing (intended uses 1 and 2). In a similar way, a single product designed for on-site (e.g. “near-patient”) use could serve in multiple settings for on-site testing shown in Storyboard B (confirmation), Storyboard C (diagnosis) and Storyboard D (differential diagnosis) if it were designed to accommodate the most challenging requirements for each workflow.

Serology tests were considered in Storyboard G (surveillance) and Storyboard H (health checks and surveys). If we pretend that these tests can be used for determination of immunity, an examination of Storyboard G suggests that the logistics for off-site testing are more than adequate since the time-to-result is not critical. However, in Storyboard H it could be a benefit to obtain test results more quickly for a new employee or an existing employee if they are trying to enter the workplace after flu-like illness. Here high-performance self-test formats could be quite useful, but the technical challenges are substantial. Off-site testing is probably acceptable despite a potential delay in work initiation. If we begin to monitor for decreased immunity with time, an off-site testing workflow will be sufficient.

As we update the list of Use Cases we are likely to add additional Storyboards, if they would be useful. We invite your feedback and interactions regarding these Storyboards.