Testing giant Quest Diagnostics is diving into the market for blood tests that aid in the early detection of Alzheimer’s disease.

The disease afflicts millions of people around the world. But early detection typically relies on costly methods such as brain imaging and cerebrospinal fluid taps. Blood tests like the one developed by Quest promise to make detection easier, less costly and more accessible.

In the near term, the chief beneficiaries will be researchers trying to identify patients for clinical trials of therapies for Alzheimer’s, according to Dr. Michael K. Racke, neurology medical director for Quest.

Blood tests could identify patients who are at risk for Alzheimer’s but who have not yet shown any signs, making them better candidates for testing new therapies, Racke said in an interview. Earlier trials often enrolled people who were symptomatic and thus less likely to benefit from treatment, resulting in trial failures.

“The problem seems to be that the treatments work in the sense that they are able to suck amyloids out of the brain,” Racke said, referring to the protein that plays a role in the progression of Alzheimer’s disease. “But you do it after the damage is done.”

Quest’s test, which has been available for about a month, is called the QUEST AD-Detect Amyloid Beta 42/40 Ratio. As the name implies, the test measures the ratio between two peptides of amyloid beta. The idea essentially is to gauge whether amyloid beta is leaving the blood and, presumably, starting to form plaques in the brain, a precursor to Alzheimer’s.

Because the test is measuring changes, patients likely will need to take it several times, Racke said. Research is aiming to pinpoint the best intervals, as well as how the test performs in diverse populations and in people with conditions like diabetes and hypertension. Also under investigation is the time between positive blood tests and onset of Alzheimer’s symptoms.

More research could help persuade clinical trial sponsors that blood tests alone are enough to screen patients, Racke said. Clinical trials for new Alzheimer’s therapies tend to require patients undergo more costly tests, such as PET scans. For now, trial sponsors may see blood tests as complementary.

“No one yet will say that the blood test by itself is good enough,” Racke said. “They want to see more data.”

Other blood tests for Alzheimer’s include PrecivityAD, developed by a St Louis-based company called C2N Diagnostics. The C2N test also evaluates peptides of amyloid beta. Competition could also come from digital tools. Merck and digital health startup Evidation are testing whether smartphone data can play a role in Alzheimer’s drug development.

No matter who wins in the marketplace, patients are likely to welcome a new generation of tests, according to a poll commissioned by Quest and included in a research report released by the company this month. While 86% of adults express some fear about learning they may develop Alzheimer’s, 83% say they would take a blood test if the results could help researchers find better treatments.

More than nine in 10 doctors, or 96%, see blood tests as a way to screen patients for clinical trials, according to the Quest data, which is based on online surveys conducted by The Harris Poll in March. The surveys reached 501 primary care providers and 2,052 Americans aged 18 years and older.

The potential costs of blood tests pose a concern, however. More than four-fifths of doctors, or 85%, say the tests’ adoption will depend on how widely they are reimbursed, according to Quest.

The test has a list price of $500. Quest is an in-network provider with most health plans, which are expected to cover the test, subject to the patient’s benefit design. But the company does recommend that patients confirm the details of the coverage with their insurance company.

Despite the concerns, an overwhelming majority of doctors, or 94%, believe blood tests will be more cost-effective than the alternatives. And nearly nine in 10 doctors, or 87%, believe blood tests for the early detection of Alzheimer’s disease risk will increasingly become the standard of care,

While blood tests are advancing, research into potential treatments is proceeding in fits and starts.

Biogen’s new drug, Aduhelm, has faced a challenging path. The company recently withdrew an application seeking approval of the drug in Europe. The withdrawal followed a decision by the Centers for Medicare and Medicaid Services to cover the drug only for beneficiaries enrolled in clinical trials.

Despite Biogen’s travails, Americans are optimistic about eliminating Alzheimer’s, with 90% expressing hope that new therapies will cure the debilitating disease, according to the Quest poll

Doctors are less sanguine. Half doubt there will ever be a cure for Alzheimer’s, the Quest poll found. Nonetheless, more than three-quarters, or 77%, believe new therapies will turn the disease into a chronic, manageable condition.

If early intervention can, in fact, make Alzheimer’s manageable, Racke said, “that’s going to be a big paradigm shift.” 

Photo: Anastasia Usenko, Getty Images