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Blood Test Shows Promise for Diagnosing Alzheimer’s

August 10, 2020
Oskar Hansson and Sebastian Palmqvist (Photo: Björn Martinsson)
Oskar Hansson and Sebastian Palmqvist (Photo Courtesy: Björn Martinsson)

A blood test measuring phospho-tau217 (p-tau217), a major component of Alzheimer’s disease-related tau tangles, was able to discriminate participants with Alzheimer’s disease from those with other neurodegenerative diseases, according to a study published online in JAMA and presented at the Alzheimer’s Association International Conference.

“Blood tests like p-tau217 have the potential to revolutionize Alzheimer’s research, treatment, and prevention trials, and clinical care,” said study senior author Eric Reiman, MD, executive director of Banner Alzheimer’s Institute in Phoenix, Arizona. “While there’s more work to do, I anticipate that their impact in both the research and clinical setting will become readily apparent within the next 2 years.”

The cross-sectional study evaluated the p-tau217 blood test in 1402 participants from a trio of cohorts.

• Among 81 participants in a brain donation program at Banner Sun Health Research Institute, Phoenix, Arizona, the plasma p-tau217 assay discriminated between brain donors with and without the neuropathological diagnosis of “intermediate or high likelihood Alzheimer’s” (characterized by amyloid plaques and tau tangles that spread to temporal lobe memory areas or beyond) with 89% accuracy and between those with and without a diagnosis of “high likelihood Alzheimer’s” with 98% accuracy.

• In 699 participants in Sweden, the blood test discriminated between those with the clinical diagnoses of Alzheimer’s and other neurodegenerative diseases with 96% accuracy, similar to tau positron emission tomography (PET) scans and cerebrospinal fluid (CSF) biomarkers. The p-tau217 blood test’s discriminative accuracy was significantly higher than several other blood tests and magnetic resonance imaging (MRI) measurements.

• In 622 participants from Colombia, the assay began to distinguish between autosomal dominant Alzheimer’s disease (ADAD)-causing mutation carriers and noncarriers 20 years before mild cognitive impairment onset.

“The p-tau217 blood test has great promise in the diagnosis, early detection, and study of Alzheimer’s,” said study senior author Oskar Hansson, MD, PhD, professor of clinical memory research at Lund University, Sweden. “While more work is needed to optimize the assay and test it in other people before it becomes available in the clinic, the blood test might become especially useful to improve the recognition, diagnosis, and care of people in the primary care setting.”

—Jolynn Tumolo


Palmqvist S, Janelidze S, Quiroz YT, et al. Discriminative accuracy of plasma phospho-tau217 for Alzheimer disease vs other neurodegenerative disorders. JAMA. 2020 July 28;[Epub ahead of print].

New blood test shows great promise in the diagnosis of Alzheimer’s disease [press release]. Lund, Sweden: Lund University; July 29, 2020.

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