A straightforward blood test could eventually act as a kind of molecular ‘clock’ to not just indicate whether someone might develop Alzheimer’s disease, but also when it might happen.
This test was detailed in Nature Medicine on February 19, and it focuses on a pathological version of a protein called tau that circulates in the bloodstream. This abnormal tau starts building up in the brains of individuals with Alzheimer’s, often well before symptoms—like memory loss—become apparent. Once validated through larger-scale studies, this test could enable earlier intervention in the disease, potentially improving treatment effectiveness.
Moreover, it could provide a tangible biological marker, or ‘biomarker’, which could streamline and reduce the costs of clinical trials for potential Alzheimer’s treatments. Howard Fink, a physician at the Minneapolis Veterans Affairs Health Care System in Minnesota, notes, “Being able to predict if and when patients might show Alzheimer’s symptoms could assist in designing trials aimed at preventing or delaying the onset of symptoms.”
However, it’s important to be cautious, and Suzanne Schindler, a neurologist at Washington University School of Medicine in St. Louis and the study’s lead author, advises that people shouldn’t rush to get the test. (While at-home blood tests for the specific tau type discussed in the study are available, she warns against it for now.) “We do not currently recommend that any individuals who do not have cognitive impairment undergo any Alzheimer’s disease biomarker testing,” Schindler explains.
Tick tock, building a clock
When tau proteins become abnormal, they can create tangled fibers that interfere with communication between nerve cells in the brain. Brain imaging tests detecting these tangles are sometimes employed in diagnosing Alzheimer’s. Preliminary studies indicate that such imaging might also help predict when Alzheimer’s symptoms are likely to emerge.
Still, these imaging techniques have their drawbacks—they can be quite cumbersome and costly, Schindler points out. As a result, researchers have been investigating more straightforward, blood-based tests that can also monitor tau levels.
