New Alzheimer's test available to the public but experts urge caution

The first direct-to-consumer Alzheimer's test is being introduced by Quest Diagnostics but experts are concerned that the test may not be accurate and note that it has not been approved by the U.S. Food and Drug Administration (FDA).

Besides questions about the test's accuracy, many medical authorities and consumer advocates question the wisdom of consumers with no signs of Alzheimer's taking tests that claim to predict whether they are likely to get the disease later.

Besides the psychological toll of a positive result, it could also make it difficult to get health insurance, including long-term care insurance, which is costly even for healthy individuals.

Quest says its blood test, called AD-Detect, has the potential to detect abnormal levels of the beta-amyloid protein, which is associated with Alzheimer's disease and is thought to be present years before symptoms of dementia manifest.

The test sells for $399 and must be administered at a Quest Diagnostics lab through a blood sample. Results are later sent to the patient with no involvement by the patient's physician.

Quest describes the test as appropriate for anyone who has a family history of Alzheimer’s disease, is experiencing memory loss, or is experiencing early cognitive decline but experts are sounding a note of caution.

Experts urge caution

"There are no large-scale, long-term clinical trials that support the idea that the AD-Detect test can predict whether a cognitively unimpaired person will transition to cognitively impaired," said Rebecca Edelmayer, PhD, senior director of scientific engagement at the Alzheimer's Association.

"As a result, it is unclear what the results of this test may mean about your Alzheimer's risk or your health status," Edelmayer told MedPage Today. While some blood tests show promise for improving the diagnostic work-up for Alzheimer's disease, "there is a lack of data to support the broad use of these tests in primary care settings, let alone individually by consumers at home," she said.

"What they are marketing is far outside of the recommended use of Alzheimer's disease blood-based biomarkers," said Suzanne Schindler, MD, PhD, of Washington University in St. Louis, who studies Alzheimer's disease biomarkers, in a MedPage Today report.

AD-Detect is not a mail-order test and must be administered in person at a Quest Diagnostics lab. It requires a blood sample. Test results are sent directly to the patient and should be discussed with the patient's physician.

"A more hopeful future"

The AD-Detect test can be a window into a more hopeful future for those who fear the ravages of Alzheimer's disease, Quest said.

"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. Blood tests like AD-Detect hold incredible potential to make Alzheimer's disease risk assessment both accessible and convenient," said Michael K. Racke, M.D., Medical Director of Neurology, Quest Diagnostics. "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."

The Alzheimer Association's Edelmayer said Quest should subject its test to FDA testing.

"We challenge Quest to pursue a path of FDA approval that demonstrates, rigorously, that this test is valuable to clinicians and patients as part of the diagnostic process," she said.