For several diagnostic applications, whenever time-to-result or the point-of-care is crucial, a rapid test can be used. There exist different types of rapid tests but focusing on human medicine, the ‘de facto’ standard is the so called lateral flow assay. This assay can be analysed using photometric methods in order to obtain a real quantitative result.
A typical readout device is what we call a hardware reader. Hardware implies that we are talking about a real device which costs money, is an extra piece one has to carry around, has to be potentially updated and in some circumstances, is a disposable.
As we can infer from the term photometric, we need a camera as the main ingredient to the overall reader recipe. This box can be surely ticked by a smartphone. Hence the raising power of the ubiquitous smartphones and the increasing demand for telemedicine have forged the idea of using the device right at your fingertips to evaluate rapid tests, on demand and on premise.
- A rapid test cassette can be different for each product, hence we had to deal with a potential versatility in terms of different test cassettes and test types.
- Variety of smartphone models, especially given the fragmentation of the Android market.
- Since the technology should be applicable for home- and professional use, we had to deal with different environments.
- In the case of medical devices for home use, we had to ensure that the product is easy to use, especially the diagnostic part, i.e. scanning a rapid test cassette.
- The technology itself was expected to power a variety of medical products, creating a new challenge for certification.
- Numerous tests are required to ensure the safety of such a product. When it comes down to manufacturing, incoming goods inspection requires even more testing.
- For the analysis of a rapid test, an illustration of the test cassettes is necessary. We call this the overlay, which must be drawn on the device to guide the user where to locate the device. Additionally, the overlay contains information about the features on the test cassette, i.e. batch information, sample drop, viewport where the test bands are visible. We have developed a flexible overlay creation process during which the main features of a rapid test cassette are positioned. These overlays can be created and rolled out in the field very fast.
- Since each device is different, we have implemented a process that must be enabled for each device individually to ensure correct and robust quantification. Therefore for each smartphone and medical product combination, a proof in terms of CV and recovery must be defined and found. After that, the smartphone can be enabled remotely. So neither does the app need an update, nor is the version increased.
- We designed the technology itself as a software module and documented it accordingly.
- Due to different environments, we have implemented metrics. These metrics rate the environment the user is currently in and give further guidance, if the analysis of said test cassette is disturbed and could lead to an incorrect value.
- We designed and developed a laboratory experience management tool for in-house measurements for incoming goods inspection, calibration of rapid tests, quarterly quality assessments for monitoring tests in the field and for the device qualification process.
Advantages compared to a classic hardware reader
- Batch information can be adjusted remotely.
- A reading device for multiple different tests combined in an app for the smartphone, the lab in your pocket.
- Adaption to new tests can be done in minutes.
- The entire technology is designed as a software module and documented as such, resulting in a very dynamic software library and a basis for future applications.
- With the metrics and user guidance we have developed, home-use is possible as we have eliminated most of the common pitfalls during the scanning process.