A blood test that detects levels of phosphorylated-tau-181 (p-tau181), a biomarker of brain changes, proved to be as effective as standard spinal fluid tests and positron emission tomography (PET) scans at detecting Alzheimer's disease, according to two separate studies published online March 2 in Nature Medicine.
Currently, clinicians rely on spinal fluid tests and PET imaging to diagnose Alzheimer's and to measure patients' response to therapies. However, spinal fluid tests involve an invasive, time-consuming spinal tap, and PET imaging is expensive and requires the use of radioactive agents.
In hopes of finding a less-invasive and more cost-effective alternative, the U.S. National Institutes of Health (NIH) funded two studies evaluating a new Alzheimer's blood test.
The first study, led by Dr. Adam Boxer, PhD, from the University of California, San Francisco, used the blood test to analyze the plasma samples of roughly 400 individuals. The test was able to differentiate the study cohort into three different groups based on levels of p-tau181: healthy individuals, those with Alzheimer's, and those with a rare neurodegenerative disease known as frontotemporal lobar degeneration (FTLD).
In a separate study, led by Dr. Oskar Hansson, PhD, from Lund University in Sweden, an international team of researchers applied the same blood test to individuals at high risk of Alzheimer's. The test was able to differentiate between Alzheimer's and other neurodegenerative diseases nearly as well as spinal fluid tests and PET scans. The blood test could help predict the future onset of Alzheimer's dementia in individuals with no or minimal cognitive impairment, Hansson and colleagues noted.
"We are poised to make dramatic advances in biomarker development for Alzheimer's disease, FTLD, and related neurodegenerative disorders," said Dr. Eliezer Masliah, director of the NIH's National Institute on Aging neuroscience division.