Blood test alone can diagnose Alzheimer's, Parkinson's without costly PET scans

South Korean researchers have identified new biomarker candidates capable of distinguishing major neurodegenerative diseases that share similar early symptoms, using only proteins found in blood. The candidates were validated against large-scale global cohort data — including the UK Biobank, the world's largest health and medical database — raising hopes for the future development of noninvasive differential diagnostic technology.

The Korea Brain Research Institute announced Monday that a research team led by Drs. Yoon Jong-hyeok, Kim Hyeong-jun and Cheon Mu-gyeong, working jointly with researchers from the Daegu Gyeongbuk Institute of Science and Technology (DGIST) and the neurology department of Chilgok Kyungpook National University Hospital, had identified common and disease-specific "plasma proteome signatures" for four major neurodegenerative diseases: Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease) and spinal and bulbar muscular atrophy (SBMA, or Kennedy's disease).

Neurodegenerative diseases are difficult to diagnose accurately in their early stages because their symptoms closely resemble one another. Currently available diagnostic methods — including cerebrospinal fluid tests and positron emission tomography (PET) scans — are either invasive or prohibitively expensive.

Previous proteomics research has also tended to focus on a single disease at a time, making it difficult to compare molecular changes common across different neurodegenerative conditions alongside disease-specific characteristics in a single study.

To address these limitations, the research team collected plasma samples from 264 patients and healthy controls and used high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) to simultaneously analyze and compare the proteomes of all four diseases.

The analysis identified key protein signatures characteristic of each disease — including metabolism-related pathological markers common to both Alzheimer's and Parkinson's diseases, and extracellular matrix-related markers more prominent in motor neuron diseases.

The team cross-validated the candidate proteins using independent large-scale datasets from the UK Biobank and the Global Neurodegenerative Disease Proteome Consortium (GNPC). Despite differences in analytical methods and study populations, some key candidate markers showed consistent directional changes and statistical significance across datasets.

The researchers expect the findings to serve as a scientific foundation for developing blood-based differential diagnostic tools for neurodegenerative diseases. The ability to simultaneously analyze molecular changes shared across multiple diseases and those unique to specific conditions could also help identify personalized treatment strategies and new therapeutic targets tailored to individual patients' disease types.

"This study goes beyond the limitations of single-disease research by systematically distinguishing common and disease-specific molecular changes across multiple neurodegenerative diseases and validating them against large-scale global data," Cheon said. "It carries significant academic and clinical implications."

The findings were published in the latest issue of Acta Neuropathologica Communications, an international journal in the field of neuroscience.