FDA clears 1st blood test for Alzheimer’s, reducing need for ‘costly’ PET imaging

The U.S. Food and Drug Administration on Friday cleared the first blood test for Alzheimer’s, potentially reducing the need for “costly” positron emission tomography (PET) scans to diagnose the disease. 

The “Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio” is indicated for the early detection of amyloid plaques—abnormal protein deposits that are a hallmark sign of the neurodegenerative disease. Authorities said the blood test provides patients with a “less invasive option” and “reduces reliance on PET scans.” 

In its announcement, the FDA highlighted estimates that 7 million individuals in the U.S. live with the disease, a number expected to nearly double by 2050. 

“Today’s clearance is an important step for Alzheimer’s disease diagnosis, making it easier and potentially more accessible for U.S. patients earlier in the disease,” Michelle Tarver, MD, PhD, director of the FDA’s Center for Devices and Radiological Health, said in a statement May 16. 

Plaques are commonly detected and visualized using amyloid PET brain scans, often years before the onset of symptoms. However, these exams are a “costly and time-consuming option and expose patients to radiation,” the FDA noted. Using a simple blood draw, the new test measures and calculates the ratio levels of two proteins—pTau217 and β-amyloid 1-42—found in plasma. This ratio is then correlated to the presence or absence of amyloid plaques in a patient’s brain, “reducing the need for a PET scan,” the FDA said. 

Prior to granting 510(k) clearance, the agency evaluated data from a multicenter clinical study of nearly 500 individual plasma samples from adults with cognitive impairment. The samples were testing using the Lumipulse blood test and compared against amyloid PET and cerebrospinal fluid examinations. About 91.7% of those with positive results had the presence of amyloid plaques on PET or spinal fluid testing. Fewer than 20% tested received an indeterminate Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio result.  

“These findings indicate that the new blood test can reliably predict the presence or absence of amyloid pathology associated with Alzheimer’s disease at the time of the test in patients who are cognitively impaired,” the FDA said in its announcement. “The test is intended for patients presenting at a specialized care setting with signs and symptoms of cognitive decline. The results must be interpreted in conjunction with other patient clinical information.”

Possible false-positive or false-negative results are the primary risks associated with the Lumipulse blood test. The former could potentially lead to inappropriate diagnoses, unnecessary treatment and psychological distress. False negatives, meanwhile, could lead to additional unnecessary diagnostic tests and delays in effective treatment. “Importantly,” the FDA said, the Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio is not intended as a screening or standalone diagnostic test, with other evaluations needed to help determine treatment options. 

Authorities reviewed the application from Fujirebio Diagnostics under the 510(k) premarket notification pathway. This gives companies the chance to demonstrate that a newly submitted product is “substantially equivalent” to another legally marketed device. Authorities found the blood test to be adequately similar to the the Lumipulse G β-amyloid Ratio (1-42/1-40), a previously cleared cerebrospinal fluid test from the same manufacturer. 

Malvern, Pennsylvania-based Fujirebio Diagnostics—a subsidiary of the larger Tokyo-headquartered Fujirebio—celebrated the decision on Friday, noting its test also has scored breakthrough device status. It utilizes Fujirebio’s fully automated Lumipulse G1200 instrument, which is “widely available” in labs throughout the U.S.

“The lack of effective, accessible and minimally invasive diagnostics for AD contributes to its late diagnosis and inadequate treatment,” Monte Wiltse, MBA, president and CEO of Fujirebio Diagnostics Inc., said in a statement, “The Lumipulse G pTau 217/ β-Amyloid 1-42 Plasma Ratio test will go a long way to assist physicians and patients to obtain an AD diagnosis in early stages of the disease, when interventions are more effective.”

The clearance comes as U.S. radiology providers have experienced rising volumes of PET scans to assess Alzheimer’s and other diseases. Los Angeles-based imaging center operator RadNet Inc. reported its first quarter earnings results earlier this month, with PET/CT volumes up nearly 22.9% (or 12.2% on a same-center basis), driven by demand for brain and prostate imaging. Overall PET procedure volumes nationwide increased by 12.2% in 2024 compared with the previous year, according to IMV.

There already are a variety of lab-developed tests on the market used to detect blood-based biomarkers associated with Alzheimer’s. However, having the agency’s sign-off confirms the accuracy and opens the door for insurance coverage and more widespread use, AARP reported Friday. Experts believe this development could help to “revolutionize” Alzheimer’s research and treatment. 

“It’s going to reduce the cost of care and diagnosis, and it’s going to give people the opportunity to get a definitive diagnosis and enter into clinical trials,” Howard Fillit, MD, co-founder and chief science officer of the Alzheimer’s Drug Discovery Foundation, told the association.