Alzheimer’s disease may be more easily detectable using a new biomarker blood test, according to a recent study.
The study, led by a University of Pittsburgh School of Medicine researcher, was published in the journal Brain on Dec. 27. It showed that testing for the biomarker known as brain-derived tau, or BD-tau, could detect Alzheimer’s more accurately than current blood tests.
While current tests can detect proteins – such as amyloid plaques and tau – that are associated with Alzheimer’s, those tests are not completely reliable.
“At present, diagnosing Alzheimer’s disease requires neuroimaging,” said senior author Thomas Karikari, PhD, assistant professor of psychiatry at Pitt Med. “Those tests are expensive and take a long time to schedule, and a lot of patients, even in the U.S., don’t have access to MRI and PET scanners. Accessibility is a major issue.”
Some forms of tau, a protein that stabilizes the nerve cells, can exist outside the brain and are not directly associated with Alzheimer’s. Because of this, neurodegeneration found using existing Alzheimer’s blood tests could come from other dementia-related conditions, such as Parkinson’s.
To improve the accuracy of Alzheimer’s detection, Karikari helped design an antibody that easily binds to BD-tau, a biomarker for Alzheimer’s found in the brain, while avoiding free-flowing “big tau,” found outside of the brain.
“The most important utility of blood biomarkers is to make people’s lives better and to improve clinical confidence and risk prediction in Alzheimer’s disease diagnosis,” Karikari said in a press release.
The study included 600 patient samples, some of whom had early Alzheimer’s and others who were diagnosed after their deaths.
“The tests showed that levels of BD-tau detected in blood samples of Alzheimer’s disease patients using the new assay matched with levels of tau in the [cerebrospinal fluid] and reliably distinguished Alzheimer’s from other neurodegenerative diseases,” the release read.
Brain autopsies also proved that the amount of BD-tau in the blood is linked to the severity of amyloid plaques and tau tangles in the brain tissue.
Next, Karikari plans to perform a larger scale study of the BD-tau test. This will include older adults with and without Alzheimer’s and those from different racial and ethnic backgrounds.
“A blood test is cheaper, safer and easier to administer, and it can improve clinical confidence in diagnosing Alzheimer’s and selecting participants for clinical trial and disease monitoring,” he said.