So many stories about so many Alzheimer’s tests fall short in explaining why sensitivity and specifity is so important in such test – and why some may choose not to be tested. This story wasn’t bad but we point out areas for improvement.
So many reports of potential tests for Alzheimer’s Disease have been announced recently that one might wonder what exactly is newsworthy about yet another announcement of a small study proclaiming preliminary results, particularly when the source is the founder of the company developing this test. This story about a blood test for antibodies that appear to be associated with Alzheimer’s meets almost all our specific criteria, but it would have been a better story if instead of merely announcing a “New Blood Test for Alzheimer’s” it had led with what distinguishes this potential test from others in development.
The real challenge of diagnostic tests for a condition like Alzheimer’s is that you want a very specific test. That means that if we say you’re going to develop Alzheimer’s, you will. Though the story reports that the test correctly identified 92 out of 100 patients who didn’t have Alzheimers, what you really want to know is whether a person who tests positive or negative today is going to develop Alzheimers in the next 1, 2 or more years. The study didn’t do this and that’s the key problem with the study and the reporting of these very preliminary results.
Memory loss with aging causes tremendous fear in our society – often for good reason. Alzheimer’s is particularly challenging because it can be hard to diagnose in its early stages and because there are no effective treatments that meaningfully slow the progression or ultimate outcome of this disease. Stories about potential tests need to acknowledge the fear, in part by clearly explain not only the potential benefits, but also the limitations and potential harms of tests.
The story includes a tentative estimate of what this sort of blood test might cost if it is approved.
It would be difficult for readers to get a true sense of the value of this test from this story. Readers should have been told more clearly that in this study, the test failed to correctly identify 4 percent of the Alzheimer’s patients and it mislabeled more than 7 percent of the healthy participants. Also, the phrase that “knowing early has many advantages” is likely to create a misperception about the potential benefits of testing – at least until some treatments are developed. The story mentioned only two potential benefits, financial planning and the ability to participate in clinical trials of experimental treatments.
The story does not discuss the potential harms of this sort of test. As mentioned above, some healthy people would be told in error that they have signs of Alzheimer’s Disease. Such a misdiagnosis could have profoundly grave consequences.
Although the story does include the results reported by the researchers, notes the small number of individuals in the study, and points out the preliminary nature of this work; it falls short. Although the headline proclaims "Blood Test May Spot Alzheimer’s Before Symptoms Appear," as the story points out lower down, the researchers have not yet studied people over time, so they cannot make any claims about predictive power. And, indeed, that’s really what people want to know, whether someone with some memory problems is going to progress to Alzheimer’s Disease, something that these researchers have yet to investigate. Then the lead sentence states the test is 96 percent "accurate," which is not the full story. The researchers reported that this blood test correctly identified 96 percent of Alzheimer’s patients and 92.5 percent of healthy people. The story would have been better if it had pointed out that the second number means that as things stand, for every 100 healthy people tested, seven or eight would be misdiagnosed as having signs of Alzheimer’s, a frightening result for those individuals.
The story does not exaggerate the extent or severity of Alzheimer’s Disease. However, it might have been helpful to include some description of the sort of individual who might consider using this sort of test. Stories like this need to be clear that since there is no meaningful treatment currently available for Alzheimer’s disease, many individuals may not want to be burdened with the prospect of impending dementia when there is no known way to do anything about it. The story would have been better if rather than focusing on individuals and the fearful prospect of Alzheimer’s, it had given more attention to the most likely near-term use for Alzheimer’s tests: as aids to researchers studying potential treatments in controlled trials.
The story includes a spokesperson from the Alzheimer’s Association. It does not appear that this group was involved with this study. We would have preferred hearing from an independent scientist rather than someone from an advocacy group. Nonetheless the Association spokesman adds some important perspectives. The story does point out near the top that the lead researcher is the founder of the company developing the test.
A strength of this story is that it prominently points out that many other potential tests for Alzheimer’s Disease are being developed. The story would have been better if it had explained why some people might choose not to be tested.
Deep in the story, it explains that "if all goes well" the developer is hopeful the test could be available within a year. That is followed by an Alzheimer’s Association spokesman saying this is "preliminary." So the developer’s optimism is tempered somewhat.
This rating is a close call. The story does include comments pointing out that there are a number of other tests for Alzheimer’s Disease being developed, but it might have been better to frame the headline and lead in a way that immediately makes clear to readers where this test fits in the context of other research. The lead could have used a phrase such as “one more potential test for Alzheimer’s enters the pipeline.”
The story includes interview quotes and does not appear to rely on a news release.