Paper diagnostic test strip. Image: McMaster University
This news release reports on the development of paper test strips that amplify DNA or RNA from blood, sweat or urine and determine if the person taking the test has a disease. The strips are made of a polymeric sugar film integrated with the paper device. Once a sample is applied the paper changes color to indicate the presence of a marker for a “specific bacterium, virus, or even cancer,” according to the release. The researchers quoted in the release claim that these test strips can be easily and inexpensively manufactured and, because they are portable, could be used to diagnose or self-diagnose illness (such as Ebola) in remote areas before the subject even knows they are ill. But the release does not make clear how such a test could be used to diagnose and differentiate between the multitudes of different diseases and conditions that afflict humans. Besides skirting other important details such as ballpark cost of the strips and data backing up claimed benefits, the release doesn’t put the paper test in context. While the idea of a “simple” paper test to check for illness may sound novel to the public, paper diagnostic tools have been under development since at least 2007.
Some diseases are contagious long before the patient has any symptoms. If a person could be diagnosed as contagious in an asymptomatic stage, then the spread of infection could be slowed or halted. A rapid test allowing patients tested in a clinic to know before they left if they had influenza or a cold, strep or a viral sore throat, would be advantageous because it would allow faster targeted treatments. Because such a diagnostic tools are predicted to be relatively inexpensive, portable, and easy to use, they might also hold enormous potential for helping health professionals in the developing world to quickly and accurately diagnose and treat disease.
While the release says that the test strips would be inexpensive, there is no indication of what exactly that means. Also, the assumed necessity of multiple strips for different diseases means a wide variety of test strips would be necessary. There is no indication of how the strips might compare in cost to common laboratory diagnostic tests.
We know that this research is preliminary and that it might be difficult to give an accurate figure. But if it’s not too early to claim these tests “can confirm presence of infections, some cancers, even before patients feel symptoms,” then it’s not too early to give some sense of what the test might cost.
The release indicates that it would be good to diagnose these diseases quickly and cheaply, but there are no hard numbers on how accurate the test strips are or how beneficial it is to diagnose a cold early. While the spread of disease might be a consideration, that is not mentioned in the release. The release doesn’t tell readers how sensitive the paper diagnostics are, or whether their sensitivity and accuracy vary from illness to illness or from medium to medium. For example, does sensitivity vary depending on whether they are analyzing blood or urine?
As with all diagnostic tests, there is the risk of false or missed diagnosis that this news release doesn’t address. One can envision a scenario where cheaper, easier-to-use diagnostic tests lead to more frequent testing in situations where tests wouldn’t have been used before. The increased volume of testing could lead to more false-positive results with resulting unnecessary anxiety and treatment.
There is no mention of any metrics in this news release. No indication of how well the DNA or RNA amplify or how accurately this occurs. There is no indication of false positive or negative results either. In general, the science behind this development is left out of the news release.
The release does not engage in disease mongering.
The news release lists all the funding sources for the project. All of the authors are McMasters University faculty or staff. The only corporate funder is Pro-Lab Diagnostics. It is unclear if any of the authors have conflicts of interest with this funding source.
There is no mention of which alternative or conventional diagnostic tests the paper strips might replace.
The news release makes it clear that this technology is not currently available, but says it “could be commercialized quickly.” That seems a bit optimistic to us, but we’ll give the benefit of the doubt here.
In assessing the novelty of the test we took into account that paper diagnostic tools are not a new concept. Organizations such as Diagnostics For All have been working in this field since at least 2007, and paper diagnostic tools have also garnered significant news coverage. For example, MIT Technology Review listed paper diagnostics one of their 10 “breakthrough technologies” in 2009. The field is sufficiently active that there have been at least three different review papers over the past couple of years on research into paper diagnostics: here, here and here. Without some context regarding the field, it’s unclear what is novel about these new research findings or how they advance paper diagnostics.
We’ll give the release a pass for this criteria even though the release talks about a new diagnostic test that “can change the medical landscape.” However, we already addressed the question of novelty and won’t ding the sponsor twice for making this claim.
Systematic, Criteria-Driven
Monday at #ADA2021, an infectious disease epidemiologist, a journalist, and a researcher shared perspectives on communication of risk in the era of COVID-19: http://ow.ly/ROfR30rMeE7 @AstleyCM @garyschwitzer @berthahidalgo @ADA_DiabetesPro
Shoutouts to @susan_bewley @drkevinknopf @MichaelBaum11 in this call for more than fawning coverage from press releases for these kinds of stories.
Also, linked history inside goes back 5 years just on Grail apparently trying to become Holy Grail. https://twitter.com/garyschwitzer/status/1408849696416841731
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