he U.S. Food and Drug Administration (FDA) has cleared a new blood test that promises to assist physicians in determining whether memory problems in older adults may be related to Alzheimer’s disease. The test, known as Elecsys pTau181, was developed through a collaboration between Roche Diagnostics and Eli Lilly, and is intended for adults aged 55 and older who exhibit early signs of cognitive decline.
“By bringing Alzheimer’s blood-based biomarker testing into primary care, we can help patients and their clinicians get answers sooner to support them earlier in their journeys,” said Brad Moore, president and CEO of Roche Diagnostics North America.
The Elecsys pTau181 test measures levels of phosphorylated tau 181 (pTau181), a protein found in blood plasma that is associated with Alzheimer’s and other neurodegenerative diseases. Elevated levels of pTau181 indicate a higher likelihood of underlying Alzheimer’s pathology. In clinical studies involving 312 participants, the test successfully ruled out Alzheimer’s disease 97.9% of the time, according to Roche.
Laura Parnas, director of medical and scientific affairs at Roche Diagnostics, emphasized the test’s role as a preliminary screening tool: “When the test result is negative, there’s a very high likelihood the person does not have Alzheimer’s-related pathology. However, a positive result still requires follow-up clinical evaluation and confirmatory testing for amyloid plaques to establish a definitive diagnosis.”
The FDA’s approval of Elecsys pTau181 marks the second blood-based diagnostic tool cleared this year for Alzheimer’s evaluation. Earlier in May, the agency approved Fujirebio’s Lumipulse test, which detects a different set of proteins associated with the disease. Experts suggest that having multiple biomarker-based tests available may enhance clinicians’ ability to assess and monitor brain health.
“Access to different blood-based tests measuring diverse biomarkers provides a broader understanding of brain health in early Alzheimer’s disease,” explained Dr. Richard Isaacson, a preventive neurologist and Alzheimer’s researcher. He added that physicians often use panels of tests rather than a single biomarker to stage disease progression more accurately.
Despite the promise these tests offer, specialists caution that careful interpretation is essential. “We must be cautious with widespread adoption due to potential false positives,” Isaacson noted. “The medical field is still learning how to apply these test results effectively in clinical practice.”
Nevertheless, the Alzheimer’s community sees the FDA clearance as a critical advance. Joanne Pike, president and CEO of the Alzheimer’s Association, described the Elecsys test as an important step toward expanding access to diagnostic tools. “By using a ‘rule out’ tool in primary care, we can quickly identify patients who are unlikely to have Alzheimer’s, while ensuring those at risk are referred for appropriate testing and early intervention,” she said.
Roche confirmed that the Elecsys pTau181 test will be available nationwide through its network of approximately 4,500 laboratory instruments. Experts agree that while early-stage blood testing for Alzheimer’s is still evolving, these developments represent significant progress in managing cognitive health.
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