When a patient complains of memory loss or has confusion about time and place, a doctor might not know immediately whether it’s normal aging or Alzheimer’s disease (AD). But a new test called DISCERN – founded by SYNAPS Dx, an Alzheimer’s disease diagnostic company – seeks to make it easier for patients and providers to accurately identify AD even at its earliest stages.
Doctors currently use different tools and methods to diagnose Alzheimer’s, including medical tests, psychiatric evaluations and a variety of brain scans. Yet, these current diagnostic tests can be expensive, invasive and overwhelming for patients, families and providers, Frank Amato, CEO and president of SYNAPS Dx, told Seasons:
“For many years in this country and around the world, there have been a number of different tests that have been developed in order to try to determine whether someone has Alzheimer’s,” he said, “but what separates us from those tests is that we take small skin samples from patients who are diagnosed with dementia and we are able to show greater than 95% accuracy for both sensitivity and specificity with our tests.”
How does the diagnostic test work?
Patients who have been diagnosed with dementia could be eligible for taking the DISCERN diagnostic test. A physician submits a patient requisition form on behalf of the patient, and SYNAPS Dx will send a kit containing instrumentation and information on how to administer the test to the physician. The provider will use the test to collect a single 3-millimeter skin sample (also known as a skin punch biopsy), which is taken as a regular blood drop.
At the SYNAPS Dx lab, scientists will incubate and grow the sample, and evaluate it using three different assays (analyses) to find key proprietary biomarkers, which help differentiate AD from other forms of non-AD dementias, even in the early stages of the disease.
“Unless the patient has been diagnosed with dementia, we don’t recommend using our test because we’ve never studied it in a population of patients who haven’t been diagnosed with dementia,” said Amato. “One thing I will draw additional attention to is, we have no control over whether the physician has accurately diagnosed dementia or not before taking the skin sample and sending it back to our laboratory.”
He added the tests do not look for a buildup of amyloid plaques (proteins that form in the spaces between nerve cells and play central roles in AD) and tau proteins (which helps stabilize neurons in the brain) like other tests do, including brain scans. This is a key difference between the DISCERN test and currently available tests.
Amato said results take about seven to eight weeks and are sent back to the ordering physician, who then communicates to the patient. However, while the new diagnostic test is encouraging, some say more work needs to be done to ensure accuracy and validity.
“Right now, these tests are designed to be tools to aid in the diagnosis, but they cannot – on their own – deliver a diagnosis,” Rebecca Edelmayer, PhD, senior director of scientific engagement at the Alzheimer’s Association, told Seasons. “The DISCERN test analyzes PKC signaling markers collected from a skin biopsy. These markers have not yet been validated in large controlled clinical trials to support their use as a diagnostic for Alzheimer’s disease.”
How valid and accurate are the tests?
According to Amato, the three tests analyzed in the lab show greater than 95% accuracy for both sensitivity and specificity. Researchers from the Rockefeller Neuroscience Institute started most of their testing in 2015 and published results in 2017.
Researchers ran all three assay (tests) on 170 people with dementia and followed them until they died. They found the tests were 95% accurate in both sensitivity and specificity, using autopsies to validate those patients had AD.
“Each of these tests in and of themselves are independently accurate and are greater than 95%,” he said. “We’ve decided to make them bulletproof by putting the three tests together.”
But Edelmayer said because the tests do not have clearance from the U.S. Food and Drug Administration (FDA), they cannot be considered or marketed as an FDA-cleared diagnostic.
“It’s important for consumers to be informed about how broad or not these tools have been evaluated to date, what they do and do not tell us,” she said. “At this time, there is no single test that can tell you if you have Alzheimer’s or not. Talk to your doctor if you’re experiencing memory problems and they conduct a series of tests to determine the cause of your memory loss.”
However, Amato stressed that because the tests are conducted in a lab certified by the Centers for Medicare and Medicaid Services, the process is safe for patients, and both patients and providers can request and use the test even if it’s not currently approved by the FDA.
How much does it cost?
“It doesn’t cost the patient anything if they’re a Medicare patient,” Amato said. “This is a disease of elderly patients, so if you’re a Medicare patient, this is where the vast majority of patients come from.”
Currently, SYNAPS Dx has not worked with BlueCross BlueShield, UnitedHealth Group, Anthem or other major health care payers to cover the cost of the tests for patients not covered under Medicare.
What comes next?
While the field of Alzheimer’s diagnostics is moving forward rapidly, experts believe additional trials and studies should be conducted before the new tests are put to use by more people.
“We’re encouraged to see there are multiple avenues and markers being explored in the diagnostic space, including this skin puncture test,” Edelmayer said. “But these are very early. An important step in moving these tests forward for broader use is to study them in large-scale clinical trials.”