For the first time, people concerned about their risk of Alzheimer’s disease can request a blood test online and receive the results in the privacy of their homes.
This may seem interesting at first glance, but the development has Alzheimer’s disease researchers and doctors up in arms.
The blood test of Quest Diagnostics , AD-Detect, measures elevated levels of beta-amyloid proteins, a hallmark of Alzheimer’s. Introduced in late July, the test is primarily aimed at people aged 50 and over who suspect their memory and thinking may be impaired, and people with a family history of Alzheimer’s or genetic risks for the disease.
Given that Alzheimer’s is among the most feared of all medical conditions, along with cancer, this could be a sizable market indeed. Nearly 7 million older adults in the U.S. have Alzheimer’s, and that number is expected to double by 2060 without medical advances.
But Alzheimer’s researchers and doctors are not convinced that the Quest trial is backed by solid scientific research. The possibility of false-positive results is high, as is the likelihood that older adults will not understand the meaning of their results, they say.
The test should only be carried out under the supervision of a doctor, if at all, experts advise. And, originally priced at $399 (recently discounted to $299) and not covered by health insurance, it’s not cheap.
Although blood tests for Alzheimer’s disease will likely become common in the coming years, the Alzheimer’s Association said it is premature to offer such a test directly to consumers.
For its part, Quest, which also sells direct-to-consumer tests for sexually transmitted diseases and several other conditions, suggests that older adults can be trusted to respond responsibly to AD-Detect results.
The test is not intended to diagnose Alzheimer’s disease, the company stressed. Instead, it is intended to help assess an individual’s risk of developing the disease. But under a new proposed biological definition of Alzheimer’s, excess amyloid could automatically trigger a “preclinical” Alzheimer’s diagnosis.
Michael Racke, medical director of neurology at Quest, said individuals who test positive may be inspired to talk to their doctors about cognitive symptoms and seek comprehensive evaluations from dementia specialists. Others may just want to adopt behaviors associated with brain health, such as getting more exercise and maintaining healthy blood pressure, blood sugar, and cholesterol levels.
“People who do consumer-initiated trials are often very motivated to find out what they can do to help reduce their risk of disease,” he said.
To get tested, a person first needs to go to the AD-Detect website and report that they are experiencing mild cognitive decline and have at least one other risk factor. (Complaints of this kind reported by patients themselves are often unreliable, experts note.) The order then automatically goes to a doctor paid by Quest, who will order a blood test at a Quest lab.
Results classifying a person as low, medium or high risk will be provided in a secure patient portal. Post-test follow-up is not mandatory, but individuals can speak with a Quest-paid doctor if they wish. (There is a separate $13 “medical service fee”).
New research from the University of Michigan confirms that older adults will take the results seriously: 97% of seniors said they would take steps to improve their brain health when receiving a positive result on a blood test, while 77% said they would consider changes to financial or end-of-life plans.
But scientists and doctors worry that Quest has not published any peer-reviewed studies documenting the test’s validity.
The company’s preliminary data released at the 2022 Alzheimer’s Association International Conference in San Diego suggests there is a relatively high likelihood of false-positive results, said Suzanne Schindler, associate professor of neurology at the University of Washington School of Medicine.
This is a significant problem because telling someone they have biological changes associated with Alzheimer’s disease is “a big deal and you want to be as accurate as possible,” Schindler noted.
Racke said at least three scientific studies that provide more details about the AD-Detect test have been submitted to medical journals and could be published by the end of this year.
Experts also question the usefulness of the test, since a positive result (indicating abnormal levels of amyloid in the blood) does not mean that an individual will definitely develop Alzheimer’s disease. Amyloid in the brain builds up slowly over decades, typically starting in middle age, and becomes more common as people age.
“This test gives a mixed answer. We don’t know if you will get dementia, or when symptoms might start, or, really, how high the risk is for any individual,” said Meera Sheffrin, medical director of Stanford Healthcare’s Senior Care clinic.
Additionally, the cognitive symptoms that prompt someone to get tested may be due to a wide variety of other causes, including mini-strokes, sleep apnea, thyroid problems, vitamin B12 deficiency, or drug interactions.
If an older adult becomes anxious, depressed or hopeless upon learning they are at risk for Alzheimer’s — another source of concern — “they may not undergo further evaluation and seek appropriate care,” said Rebecca Edelmayer, senior director of scientific engagement of the Alzheimer’s Association.
Research from the University of Michigan confirms the potential for misunderstandings. Upon receiving a positive blood test result, 74% of seniors said they believed they were likely to develop Alzheimer’s disease and 64% said they were likely to experience significant distress.
Because the science behind blood tests for Alzheimer’s disease is still developing and because “patients may not truly understand the uncertainty of test results,” Edelmayer said, the Alzheimer’s Association “does not endorse the use of AD testing. -Detect by consumers.”
The Quest blood test is one of several developments altering the landscape of Alzheimer’s treatment in the United States. In early July, the FDA granted full approval to Leqembi, an anti-amyloid therapy that slightly slows cognitive decline in people with mild cognitive impairment and early-stage Alzheimer’s disease.
Early detection of cognitive symptoms and diagnosis of cognitive dysfunction have taken on greater importance now that this disease-modifying medication is available.
Also in July, a working group convened by the National Institute on Aging and the Alzheimer’s Association proposed a new definition of Alzheimer’s disease to be used in clinical practice.
Previously, Alzheimer’s disease could only be diagnosed when there was evidence of underlying brain pathology (amyloid plaques and tau tangles), as well as cognitive symptoms (memory loss, poor judgment, disorientation, among others) and associated disabilities (difficulty managing finances, wandering, self-care issues, and more).
Under the new definition, Alzheimer’s disease would be defined purely on a biological basis, as a “continuum that is first evident with the appearance of pathological changes in the brain,” including amyloid accumulation, according to a draft report from the research group. work.
This would mean that “you could get a positive Quest test result and be diagnosed with Alzheimer’s disease if these guidelines are adopted, even if you are cognitively normal,” warned Eric Widera, professor of medicine at the University of California-San Francisco.
Demand for follow-up assessments by dementia specialists will likely be high and contribute to already long waits for treatments, he suggested.
Additional concerns about the test relate to safeguarding privacy and the potential for discrimination. No federal law protects people who receive Alzheimer’s biomarker results from discriminatory practices, such as employment discrimination or denial of life, disability, or long-term care insurance. (The Genetic Information Non-Discrimination Act applies only to genetic testing).
And “laws that typically protect the privacy of health information don’t apply in this space,” said Emily Largent, assistant professor of medical ethics and health policy at the University of Pennsylvania’s Perelman School of Medicine.
Notably, HIPAA, the Health Insurance Portability and Accountability Act, does not extend to laboratory tests marketed directly to consumers.
Bottom line: Before taking a test, “seniors need to ask themselves, ‘Why do I want to know this? What will I do with the information? How will I react? What would I change in the future?’” said C. Munro Cullum, a neuropsychologist and distinguished professor of clinical psychology at the University of Texas Southwestern Medical Center. “This test needs to be used very carefully and with great forethought.”
*Editor’s Note: KFF Health News, formerly known as Kaiser Health News (KHN), is a national newsroom that produces in-depth journalism on health issues and is one of the primary operating programs of KFF – the independent source for health policy research and journalism.
Source: CNN Brasil
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