A blood test to help diagnose Alzheimer’s disease has gone on sale in the United States, despite lacking approval from that nation’s Food and Drug Administration (FDA).
The PrecivityAD blood test from C2N Diagnostics of St Louis is aimed at people aged 60 and older who are experiencing cognitive problems and are being evaluated for Alzheimer’s. The test predicts whether a patient has amyloid plaques in the brain, which are common in Alzheimer’s patients.
Currently, diagnosis for Alzheimer’s, the most common form of dementia, involves expensive PET brain scans.
Associated Press reports that the PrecivityAD test is available for sale in most US states and Europe. Only doctors can order the test and results are returned within 10 days.
“It measures two types of amyloid particles, plus various forms of a protein that reveal whether someone has a gene that raises risk for the disease. These factors are combined in a formula that includes age, and patients are given a score suggesting low, medium or high likelihood of having amyloid build-up in the brain.”
The company is seeking FDA approval and says it will publish results.
“This blood test very, very accurately predicts who’s got Alzheimer’s disease in their brain, including people who seem to be normal,” Alzheimer’s researcher Dr Michael Weiner told the New York Times when news of the research broke.
“It’s not a cure, it’s not a treatment, but you can’t treat the disease without being able to diagnose it. And accurate, low-cost diagnosis is really exciting, so it’s a breakthrough.”
Blood tests would help Alzheimer’s researchers by making clinical trials of potential treatments faster and cheaper.
“But the ability to diagnose Alzheimer’s with a quick blood test would also intensify ethical and emotional dilemmas for people deciding whether they wanted to know they had a disease that does not yet have a cure or treatment,” Dr Weiner said.
There are misgivings about the announcement.
Andrea Gilmore-Bykovskyi, who runs a research lab at the University of Wisconsin School of Nursing, is concerned that hyped advances in the field have rarely delivered better outcomes for patients.
“My concern is that it’s insensitive to … people who are living with Alzheimer’s right now to call this a ‘breakthrough’ when they still don’t have basic needs met.”
But, despite saying the test needed more thorough trials and FDA approval, many scientists tasked with improving Alzheimer’s diagnosis are bullish.
“Based on the data, it’s a big step forward,” said Rudolph Tanzi, a professor of neurology at Massachusetts General Hospital and Harvard Medical School, who was not involved in the C2N Diagnostics research.
“The holy grail in medicine is the blood test. It’s easy, highly scalable, and hopefully not too expensive,” Renaud La Joie, an Alzheimer’s biomarker researcher at UCSF told Forbes.
The most immediate uses of blood tests would be to speed up and lower the cost of clinical trials and to allow doctors to diagnose or rule out Alzheimer’s for patients with dementia if they and their families sought that information to help them plan for what lay ahead.
“The certainty of a diagnosis could help patients, family caregivers and physicians themselves cope,” Dr. Reiman said.
The C2N Diagnostics’ blood test is not intended for general screening or for people without symptoms. But ideally, blood tests could eventually be used to help diagnose people earlier. People experiencing mild memory issues could find out if they would develop AD or another, less aggressive conditions.
Dr Tanzi hopes blood tests can one day make early detection of AD possible.
Howard Fillit, founding executive director of the Alzheimer’s Drug Discovery Foundation, which helped fund the research, says a proper evaluation for dementia takes 90 minutes, while the average doctor visit lasts 11 minutes.
“They’re not doing careful cognitive testing,” he said.
A blood test, however, fits into a typical medical exam. He wants to ‘mainstream’ Alzheimer’s care.
Would you want to know if you had Alzheimer’s before a cure or treatment is found?
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