Beyond Amyloid and Tau: Blood Testing for Neurodegenerative and Psychiatric Disease

Blood-based diagnostics for Alzheimer disease have advanced in recent years, with the US Food and Drug Administration clearing a test and multiple companies developing assays based on amyloid plaques or phosphorylated tau.¹ Now, Navneet Dogra, PhD, and colleagues are pursuing a different target: the RNA trajectory from DNA to protein. Dogra’s work hypothesized that RNA changes might precede pathology, allowing detection of dementia 1 step ahead of the pathology occurring.

The strategy began with a blood draw, followed by isolation of extracellular vesicles and particles (EVPs), and then RNA extraction.² Dogra said he ultimately aimed to develop a polymerase chain reaction (PCR) assay targeting a defined set of RNAs that changed consistently with aging, neurodegeneration, or Alzheimer disease. These test types are familiar, with PCR tests being widely used during COVID-19. In principle, the full process from blood sample to result could take 4 to 5 hours. Dogra described the concept as "taking someone's blood, extracting a set of extracellular vesicles and particles, and then looking at their RNA and understanding what is going on in the brain."

These findings were preliminary, derived from a small group of 20 to 25 patients, and Dogra described the work as a start requiring further research. The EVP approach could extend beyond Alzheimer disease to psychiatric disorders such as depression, for which no definitive diagnosis existed, and to schizophrenia, which a collaborator on the project studied. Dogra noted that diagnosing these neuropsychiatric and neurodegenerative diseases remained poorly understood, and that tracking EVP-derived RNA over time could reveal what was happening in the brain, including whether a therapy was working. Dogra said investigators needed to "identify at what time there was this first diagnosis or first detection of this cognitive decline and how it kept declining, because therapy can only work if you can diagnose.”

Dr Dogra is an assistant professor at the Icahn School of Medicine at Mount Sinai.

References

1. FDA clears first blood test used in diagnosing Alzheimer disease. Press release. May 16, 2025. Accessed October 7, 2026. https://www.fda.gov/news-events/press-announcements/fda-clears-first-blood-test-used-diagnosing-alzheimers-disease

2. Gonzalez-Kozlova E, Tichkule S, Nose Y, et al. SECmeres outperform extracellular vesicles as potential blood RNA biomarkers for Alzheimer disease. Nat Commun. 2026;17(1):5453.