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  • Alzheimer’s disease affects over 6 million people in the U.S.
  • Now there is a new direct-to-consumer blood test to help assess the risk of Alzheimer’s disease.
  • However, the only way to get a definitive diagnosis is to talk with a physician.

Quest Diagnostics launched on July 31 a direct-to-consumer blood test to detect abnormal levels of beta-amyloid, a protein involved in Alzheimer’s disease that can show up in the brain years before symptoms arise.

The first-of-its-kind test, called AD-Detect, will cost $399, plus a $13 physician service fee. The technology is the same as the AD-Detect Amyloid Beta 42/40 Ratio blood test launched by the company in early 2022, which is available with a doctor’s order.

Alzheimer’s disease affects more than 6 million people in the U.S.

Quest’s consumer test is available to people 18 years or older who are experiencing early cognitive symptoms, such as memory loss; or who have a family history of Alzheimer’s disease, are 65 years or older, or have suffered brain trauma or a head injury, even if they don’t have any cognitive symptoms.

“Blood tests like AD-Detect hold incredible potential to make Alzheimer’s disease risk assessment both accessible and convenient,” Dr. Michael K. Racke, Quest Diagnostics’ medical director of neurology, said in a statement.

Individuals who purchase the test online will be prompted to schedule an appointment at one of Quest Diagnostics’ patient service centers to have their blood drawn.

Licensed physicians oversee ordering the test and reviewing the results. Consumers can access their results online and discuss them with an independent physician at no extra cost. Results can also be shared with a patient’s regular primary care physician.

The announcement comes after the Food and Drug Administration’s full approval last month of Leqembi, a drug from Eisai and partner Biogen that reduces amyloid plaques in the brain. A clinical trial found that Leqembi slowed the advance of Alzheimer’s disease in people with early stages of the illness.

The FDA is also reviewing an application from Eli Lilly for its drug donanemab, which targets amyloid and has been found in a clinical trial to have similar benefits as Leqembi for people with early forms of Alzheimer’s disease.

Leqembi is currently approved by the FDA for people with mild cognitive impairment or mild dementia due to Alzheimer’s disease. However, “there are no safety or effectiveness data on initiating treatment at earlier or later stages of the disease than were studied [in the clinical trial],” the agency said in a statement.

Additional clinical trials would be needed to show whether giving these drugs earlier — to people with amyloid plaques in the brain, but with no cognitive symptoms — might provide benefits.

Dr. Rehan Aziz, a psychiatrist at Jersey Shore University Medical Center in New Jersey, emphasized that while screening tests such as Quest Diagnostic’s AD-Detect are important, a positive result does not automatically mean that someone has Alzheimer’s disease.

These tests ”have to be interpreted in the context of how someone is functioning and how they’re doing in their day-to-day life,” said Aziz, an associate professor of psychiatry and neurology at Hackensack Meridian School of Medicine.

A patient’s doctor will be the one to make a diagnosis of Alzheimer’s disease, which is also needed before Leqembi or another medication can be prescribed.

“If the test gives a positive result, that should lead a patient to have a discussion with their doctor about what that might mean and how they might mitigate their risk,” said Aziz. “And if the positive test means that they have Alzheimer’s, then they can start treatment early.”

If a person has a negative result on the test but is experiencing symptoms such as forgetfulness, difficulty making decisions, or trouble carrying out simple mental tasks, they should still talk to a doctor. These could be a sign of another health condition, said Aziz.

In addition to medications for Alzheimer’s disease, lifestyle changes can also lower a person’s risk of developing dementia or their dementia worsening.

“When we see patients, we recommend lifestyle measures such as walking 30 minutes a day, adopting a Mediterranean-style diet, and doing brain exercises,” said Aziz.

“People who are interested in taking a test like [AD-Detect] are probably worried about their risk for Alzheimer’s and other types of dementia,” he added. “So they might want to talk to a doctor about these lifestyle interventions, as well.”

Quest Diagnostics has released a new direct-to-consumer test that can help people determine their risk of developing Alzhiemer’s disease.