Quest launches first blood test of Alzheimer’s risk for consumers

New test for proteins, done at lab, will not need doctor's order

Lindsey Shapiro, PhD avatar

by Lindsey Shapiro, PhD |

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Quest Diagnostics has launched a consumer-initiated blood test for adults in the U.S. that assesses Alzheimer’s disease risk by measuring levels of certain forms of the amyloid beta protein, a known marker of the neurodegenerative disorder.

Called AD-Detect, the test is now the first of its kind to be directly available for consumer purchase, rather than first requiring an order from a healthcare provider. It was designed to allow individuals to have themselves tested — potentially at a much earlier time point — to better determine their risk of Alzheimer’s disease.

Adults in the U.S. — in all states except for Alaska, Arizona, and Hawaii — who are at risk for or are experiencing cognitive symptoms of Alzheimer’s can purchase the test directly on the Quest website. The cost is $399 plus a $13 physician service fee.

Doctors from an independent physician network will review the purchase and place an order for the test, which can then be conducted at any of Quest’s 2,100 labs nationwide.

“We are seeing much attention on emerging therapies for Alzheimer’s disease, but with new treatment options will come the need to make screening and diagnosis more widely available,” Michael K. Racke, MD, medical director of neurology at Quest, said in a company press release, adding, “Blood tests like AD-Detect hold incredible potential to make Alzheimer’s disease risk assessment both accessible and convenient.”

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In Alzheimer’s, the amyloid beta protein forms clumps, or plaques, that disrupt nerve cell function and drive cell death. These proteins begin accumulating in the earliest stages of the disease, before cognitive declines start.

Traditionally, an Alzheimer’s diagnosis is made only after a person already is exhibiting signs of cognitive difficulties. Moreover, that diagnosis typically involves expensive or invasive procedures, such as brain imaging scans and spinal fluid collection, to look for amyloid beta accumulation.

By the time a diagnosis is made, “irreversible damage may have already occurred, and meaningful intervention is limited,” Quest stated in a research report in May 2022.

We’re … seeing a push from consumers who have a desire to take more control of their health, including within more advanced areas like Alzheimer’s disease risk assessment.

Newer, cheaper, blood-based tests developed in recent years have enabled earlier Alzheimer’s risk detection in the earliest stages of the disease, or even before symptoms emerge.

Still, data indicate that Americans wish their doctors would start running tests for dementia, including Alzheimer’s, about 10 years sooner than what is now typically done in medical practice, according to Quest’s research report.

“We’re also seeing a push from consumers who have a desire to take more control of their health, including within more advanced areas like Alzheimer’s disease risk assessment,” Racke said.

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With that in mind, Quest developed AD-Detect, which can be requested without the need to go to a doctor first. The premise of the test is the same as Quest’s AD-Detect Amyloid Beta 42/40 Ratio test, a validated blood test launched in 2022 that requires a physician’s order.

In both assays, the ratio of two forms of amyloid beta, AB42 and AB40, are measured in a single blood sample. A lower AB42/AB40 ratio in the brain is associated with a higher risk of Alzheimer’s.

By identifying toxic amyloid accumulation before people have symptoms, such testing can allow individuals to start treatment sooner, potentially preventing or slowing the onset of disease. The test also helps rule out other causes of dementia.

It uses plasma, the liquid component of blood, taken from a single blood draw.

Quest says the AD-Detect test is for people who believe they are experiencing cognitive decline/memory issues or who are at risk for the disease. Risk factors include a family history of Alzheimer’s, an age of 65 or older, or a history of brain trauma/head injury.

While AD-Detect is consumer-ordered, physicians still oversee the process. After a person purchases a test, doctors from an independent physician network will review the provided information and place an order for the test.

The purchaser will then be prompted to schedule an appointment for a blood draw at a Quest laboratory.

Test results will be interpreted by doctors in the network and delivered as an easy-to-read report via a secure patient portal. People also can discuss the interpretation of their results with network physicians, or share them with their own doctors to decide the next steps.

Quest stressed that AD-Detect helps to evaluate a person’s risk status, but is not a diagnostic test. Findings from the test should be considered in conjunction with other evaluations under the supervision of a doctor.