Alzheimer’s Blood Test Available For Purchase, But Not Yet FDA-Approved


Key Takeaways

  • A new blood test could help doctors detect Alzheimer’s disease (AD) by measuring amyloid buildup, a hallmark of the neurodegenerative disease.  
  • While it is an exciting development, the test has not yet received approval by the Food and Drug Administration (FDA), and key data on the test’s accuracy has not been released.
  • The FDA has approved several drugs to help reduce the symptoms of Alzheimer’s, and a healthy lifestyle plays an important role for patients.

Physicians can now purchase the first blood test to help detect Alzheimer’s disease (AD). The test could make it easier for people to find out if their memory loss is a sign of cognitive impairment or simply the effects of getting older.

Currently, an Alzheimer’s diagnosis cannot be 100% confirmed until a patient dies and their brain tissue can be examined during an autopsy.

Still, physicians use an arsenal of imaging tools to help diagnose patients with AD, like positron emission tomography (PET), magnetic resonance imaging (MRI), and computerized tomography (CT).

Structural imaging tests help clinicians examine a patient’s brain for a buildup of a protein fragment called beta-amyloid—a hallmark of AD. The tests also help rule out other conditions that cause symptoms similar to AD, such as a stroke or a tumor.

“The most sophisticated methods to diagnose AD measure amyloid and tau [brain-cell protein] in the brain via a PET scan, or in the cerebrospinal fluid via a lumbar puncture,” Arjun Masurkar MD, assistant professor of Neurology and Neuroscience & Physiology at NYU Langone’s Alzheimer’s Disease Center, tells Get Meds Info. “The drawbacks are that they are either costly, in the former, or involve an invasive procedure, in the latter.”

PET imaging can cost more than $3,000 a scan and is not usually covered by insurance.

What Is Alzheimer’s?

According to the National Institute on Aging (NIA), Alzheimer’s disease (AD) is “an irreversible, progressive brain disorder that slowly destroys memory and thinking skills.”

Eventually, people with AD can lose the ability to perform everyday tasks like cooking, bathing, and toileting. According to the NIA, as many as 5.5 million Americans may have Alzheimer’s-induced dementia.

How the New Blood Test Works

PrecivityAD is the first test to detect Alzheimer’s to become available in clinics. The test is not covered by insurance or Medicare, but at $1,250, the cost is slightly lower than imaging tests like PET scans. C₂N Diagnostics, the company behind the test, also offers a financial assistance program to patients based on income.

C₂N Diagnostics co-founder and neurologist at Washington University in St. Louis, David Holtzman, MD, tells Get Meds Info that the test does not diagnose AD but, rather, it predicts which patients may or may not have amyloid accumulation in the brain.

To determine the likelihood of this buildup, the test looks at the patient’s age and measures two forms of beta-amyloid: Aβ42, and Aβ40. It also checks for a protein called ApoE, a well-known risk factor for Alzheimer’s.

“If the number is abnormal it would indicate that you have amyloid in the brain, meaning it’s likely that your cognitive impairments are due to AD,” Holtzman says. “It doesn’t prove it; it suggests that that’s likely the cause. If it’s negative, it would indicate that it’s likely that your cognitive impairment is not due to AD.”

The test is only for patients over the age of 60 who are experiencing cognitive impairment symptoms. Clinicians can order the test for patients, but it is not available for consumers to purchase directly.

Mixed Reviews From the Medical Community

Many experts in the field of neurology and Alzheimer’s research have voiced mixed opinions on the PrecivityAD blood test.

The Need for FDA Approval

Some concerns stem from the fact that the company has not obtained Food and Drug Administration (FDA) approval. However, Holtzman says that C₂N Diagnostics is in the process of obtaining FDA approval for PrecivityAD.

“It takes a lot longer to get FDA approval for anything so we started going through that process at least a year ago,” says Holtzman. “The company is confident that the test is very good and accurate and so we thought it would be valuable to make it available to patients if they want that information.”

More Data on Accuracy

Some critics also cite another drawback—the fact that C₂N Diagnostics has yet to publish any data on the test’s accuracy. Instead, the company points to the results of a study that compared the test to PET scans of 686 participants between the ages of 60 and 90 with cognitive impairments or dementia. When a PET scan showed amyloid buildup, the PrecivityAD blood test also provided a high probability of amyloid buildup in 92% of cases.

Rebecca Edelmayer, PhD

It’s not really clear how accurate or reliable the results are for all individuals and all populations that may take the test.

— Rebecca Edelmayer, PhD

Rebecca Edelmayer, PhD, director of scientific engagement at the Alzheimer’s Association, tells Get Meds Info that while this type of test is exciting, it’s vital that it delivers on the rigorous review required of a diagnostic test.

“We know that it’s only been really tested in a few 100 individuals,” Edelmayer says. “Right now, it has little data that’s been presented from individuals of underrepresented populations. Until that kind of information is available to the field, it’s not really clear how accurate or reliable the results are for all individuals and all populations that may take the test.”

Masurkar agrees that more information is needed to better understand the test’s accuracy. “We would also want to know if it can accurately distinguish between AD and Lewy body dementia, in which there can also be amyloid plaques as a secondary pathology.”

What This Means For You

While the PrecivityAD blood test has the potential to help detect Alzheimer’s disease in a less invasive and expensive way, many experts want more concrete data on its accuracy before endorsing the new diagnostic test.

Preventing and Delaying Alzheimer’s Symptoms

While there is no cure for Alzheimer’s, having an early diagnosis can provide patients with benefits like being able to plan for the future and having access to clinical trials for new drugs and treatments.

Drug Development

There are currently several prescription drugs to treat the symptoms of Alzheimer’s—and many more in development.

“There are actual FDA-approved treatments for Alzheimer’s that help with enhancing cognition, and these types of treatments typically work at the early stage of the disease better than they would at a later stage of the disease,” Edelmayer says. “We also know that these types of treatments may only work temporarily, so that’s why we need to continue to do more research to develop new treatments that are going to be able to change the progression of the disease process itself.”

Lifestyle Changes

Science has proven that certain treatments can help slow down some symptoms of AD-like memory loss, but studies have also shown that making healthy lifestyle changes can reduce the risk of cognitive decline.

A review of research performed by experts at the National Academies of Sciences, Engineering, and Medicine (NASEM) found encouraging but inconclusive evidence that increased physical activity, blood pressure control, and cognitive training can prevent or delay cognitive decline and dementia.

“An ounce of prevention remains the best approach,” Amit Sachdev, MD, medical director in the department of neurology at Michigan State University, tells Get Meds Info. “People who have healthy bodies and well-trained minds age more gracefully, so really keeping your body mass under control, keeping as social as you can be, and working that brain remains a very reasonable and important thing to do.” 

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