FDA approves first blood test to help diagnose Alzheimer’s

The US Food and Drug Administration has granted marketing clearance for the first blood test designed to assist in identifying the Alzheimer’s disease.

The approval marks a significant advancement in the early detection and potential treatment of Alzheimer’s, a condition affecting millions of Americans.

The newly approved test, called the Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio, is developed by Pennsylvania-based Fujirebio Diagnostics Inc. It is intended for adults 55 and older who are showing symptoms of Alzheimer’s, such as memory loss or cognitive decline.

Unlike traditional diagnostic methods that rely on expensive PET scans or invasive spinal taps, this blood test measures two key proteins in plasma – phosphorylated tau (pTau217) and beta-amyloid 1-42. The ratio of these proteins can indicate the presence of amyloid plaques in the brain, one of the defining features of Alzheimer’s disease.

“Alzheimer’s disease impacts too many people, more than breast cancer and prostate cancer combined,” FDA Commissioner Dr. Martin Makary said in Friday’s announcement.

“Knowing that 10% of people aged 65 and older have Alzheimer’s, and that by 2050 that number is expected to double, I am hopeful that new medical products such as this one will help patients.”

While not a definitive diagnostic tool on its own, the blood test is expected to serve as an important part of a broader diagnostic toolkit that includes clinical assessments, neurological exams, imaging, and cognitive evaluations. The FDA said results from the test must be interpreted alongside other clinical information.

Clinical trial data submitted to the FDA included plasma samples from 499 adults with cognitive impairment. The study found that the blood test had a 91.7% accuracy in identifying individuals with amyloid plaques confirmed through PET scans or spinal fluid analysis, and a 97.3% accuracy in confirming those without them.

Experts hailed the approval as a critical step forward, while also urging caution.

“It can provide better clarity into whether a person experiencing memory loss may have Alzheimer’s disease. They can take this test as a screening test,” Isaacson, director of research at the Institute for Neurodegenerative Diseases in Florida, told CNN.

However, Isaacson also noted that the test is not a standalone solution.

“I think the next step as a field is, we need to advance education about what these tests mean and what they don’t and who they should be used for,” he said. “Because they mean different things in different people depending on their risk factors and whether or not they have symptoms. So we’re still early.”

“Today’s clearance is an important step for Alzheimer’s diagnosis, making it easier and potentially more accessible for US patients earlier in the disease,” said Michelle Tarver of the FDA’s Center for Devices and Radiological Health.

The Alzheimer’s Association welcomed the FDA’s decision, with Chief Science Officer Dr. Maria Carrillo saying, “For too long, Americans have struggled to get a clear diagnosis. This approval brings us one step closer to changing that reality.”

The approval comes at a time when Alzheimer’s diagnoses are expected to surge. Currently, about 10% of Americans over the age of 65 have Alzheimer’s disease, a number projected to double by 2050. Meanwhile, more than 42% of people over 55 are estimated to develop some form of dementia in their lifetime.

Importantly, amyloid plaques may begin forming decades before symptoms appear, making early detection critical. Experts say this test could help identify individuals who are at risk before significant cognitive decline begins, allowing for earlier interventions and potential participation in clinical trials for emerging treatments.

Fujirebio Diagnostics CEO Monte Wiltse called the FDA’s decision a validation of the company’s vision.

“An early and accurate diagnosis will also facilitate the development of new drug therapies, which are urgently needed as the prevalence of AD increases with a rapidly aging population globally,” Wiltse said.