Home Blood Tests Show Potential for Alzheimer’s Screening

A new study published in Nature Communications suggests that self-administered, in-home finger-stick blood tests can detect Alzheimer’s disease biomarkers that correlate with cognitive performance [1]. This approach aims to move dementia risk screening out of specialized clinical settings and into the community, where early cognitive concerns often go unevaluated [1].

Key takeaways

• Capillary blood levels of p-tau217 and glial fibrillary acidic protein (GFAP) were found to correlate with various measures of cognitive function, including episodic memory and executive function [1].
• A high-risk group identified by combining p-tau217 results with memory scores performed significantly worse on cognitive and functional measures [1].
• Researchers observed that GFAP-positive participants were nearly five times more likely to report a history of heart disease, suggesting the two biomarkers may identify distinct at-risk populations [1].
• In a separate study of centenarians, higher plasma levels of neurofilament light chain (NfL)—a marker of neuronal injury—were associated with lower cognitive scores and increased mortality rates [2].

Expanding Access to Early Detection

The study, which involved 174 participants with a mean age of 66, utilized a capillary blood sampling device that allowed subjects to collect samples at home and return them by mail [1]. While the findings demonstrate the feasibility of remote collection, experts emphasize that the technology is not yet ready for clinical practice [1]. Suzanne Schindler, MD, PhD, of Washington University School of Medicine, noted that while the tool may help identify individuals at the extremes of risk, it currently lacks the precision to stratify those in the middle [1].

The research builds on the earlier DROP-AD trial, which confirmed that capillary blood samples show strong concordance with venous samples [1]. However, the current study is the first to validate the process entirely outside of supervised clinical environments [1]. Investigators set a memory threshold for the study at 1 standard deviation below age-matched norms, a deliberate choice intended to capture individuals earlier in the disease course than traditional mild cognitive impairment screenings [1].

Biomarkers and the Aging Process

While p-tau217 and GFAP are being explored for Alzheimer’s screening, other biomarkers provide insight into broader neurodegeneration. A Japanese cohort study published in JAMA Network Open identified neurofilament light chain (NfL) as a significant marker for both cognitive health and survival in the oldest old [2]. Unlike amyloid and tau biomarkers, which are specific to Alzheimer’s pathology, NfL appears to reflect complex systemic interactions, including immunity and vascular function [2]. Researchers suggest that NfL could serve as a valuable tool for assessing the health trajectories of extremely old adults [2].