Can Blood Tests Replace Brain Scans for Alzheimer's? New Study Says Yes

In a study published in JAMA Network Open, researchers at the University of California San Diego School of Medicine have uncovered a significant connection between self-reported cognitive decline and blood-based biomarkers in Hispanic and Latino adults. This finding could lead to the development of a less invasive, more accessible, and cost-effective blood test for diagnosing Alzheimer’s disease and related dementias. The study, led by Dr. Freddie Márquez, a postdoctoral scholar in the Department of Neurosciences, focused on improving early detection methods for neurodegenerative diseases. The researchers analyzed data from 5,712 Hispanic and/or Latino adults aged 50 to 86, using information from the Study of Latinos–Investigation of Neurocognitive Aging. The study found that higher blood levels of neurofilament light chain (NfL), a marker of nerve cell damage, and glial fibrillary acidic protein (GFAP), a marker of brain inflammation, were associated with increased self-reported declines in thinking and cognitive planning. Elevated levels of tau protein (ptau-181) also correlated with worsening memory. Interestingly, amyloid-beta protein (Aβ42/40)—long considered a hallmark of Alzheimer’s—did not show a strong association with subjective cognitive decline. “By including participants from underrepresented communities, we’re able to better understand how social determinants of health and comorbidities may influence cognitive trajectories and dementia risk.” “This makes our findings especially relevant for real-world settings.” It’s important to note that there’s still a lot we don’t know about the utility of blood-based biomarkers for Alzheimer’s detection,” said Márquez. “These tests have tremendous potential, but they should complement existing approaches, not replace them.” While the findings support the potential of blood tests as early detection tools, the researchers stress the need for more research before widespread clinical use.