Simple Blood Test Could Streamline Early Alzheimer's Detection

Alzheimer’s disease and related dementias are among the leading causes of cognitive decline, yet current diagnostic options are often expensive, invasive, and limited to specialized care settings. Early detection is critical, but existing tests remain inaccessible to many populations. Now, a landmark study has linked blood-based biomarkers with self-reported cognitive decline, offering a potential breakthrough in early and affordable screening for Alzheimer's and related dementias.

Researchers at the University of California San Diego School of Medicine (La Jolla, CA, USA) conducted the study using data from the Study of Latinos–Investigation of Neurocognitive Aging, part of the largest U.S. cohort on Hispanic and Latino health. The team examined proteins in the blood that are associated with Alzheimer’s pathology, including amyloid beta, tau, NfL, and GFAP. The aim was to explore whether blood biomarkers could serve as scalable, non-invasive tools for early dementia detection.

Blood samples from 5,712 Hispanic and Latino adults aged 50 to 86 were analyzed alongside self-reported measures of cognitive decline. Higher levels of NfL and GFAP correlated with declines in thinking, planning, and cognitive performance, while NfL and tau were linked to memory issues. Notably, amyloid-beta levels showed no association. The findings, published in JAMA Network Open, demonstrate that NfL may detect early cognitive changes even in seemingly healthy individuals.

These results highlight the promise of blood-based tests for diagnosing Alzheimer’s and related dementias earlier, especially in underserved populations projected to see rising prevalence. The study’s diverse sample provides insight into how social determinants and comorbidities affect dementia risk. However, researchers caution that more work is needed before integrating such tests into routine clinical practice, where they would complement—not replace—existing diagnostic tools.

“We need ways to identify underlying neurodegenerative diseases earlier in patients with cognitive symptoms,” said corresponding author Freddie Márquez, Ph.D., a postdoctoral scholar in the Department of Neurosciences at UC San Diego School of Medicine. “This study highlights the promise of blood-based biomarkers as a more accessible and scalable tool for understanding cognitive decline, particularly in populations that have been underserved by traditional methods.”

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