Exploratory Clinical Study and Validation of Blood Biomarkers for Alzheimer's Disease

Inclusion criteria

For All Participants (HV and AD groups):

• Age between 50 and 85 years
• Ability to understand and sign informed consent
• Availability for the full duration of the study (24 months)
• Fasting capability for morning sample collection (between 8:30-12:00)
• Willingness to provide blood and urine samples for biomarker analysis and biobank storage

Additional Criteria for Healthy Volunteers (HV):

• No history or current diagnosis of neurodegenerative disease
• Normal cognitive function confirmed by neuropsychological testing (e.g., MMSE score within normal range)
• No significant abnormalities on brain imaging (CT or MRI if performed)
• No use of medications affecting cognitive function

Additional Criteria for Alzheimer's Disease Patients (AD):

• Clinical diagnosis of probable Alzheimer's disease based on standardized criteria
• Cognitive impairment confirmed by neuropsychological testing (e.g., MMSE score below threshold)
• Supporting evidence from brain imaging (CT or MRI) and/or cerebrospinal fluid biomarkers (if available)
• Stable medical condition allowing participation in study procedures

Exclusion criteria

For All Participants:

• History of major psychiatric disorders (e.g., schizophrenia, bipolar disorder)
• Significant neurological conditions other than Alzheimer's disease (e.g., Parkinson's disease, stroke)
• Active malignancy or history of cancer within the past 5 years (except localized skin cancer)
• Severe renal, hepatic, or cardiovascular disease
• Current participation in another interventional clinical trial
• Known blood disorders or conditions affecting red blood cell morphology or function
• Recent blood transfusion (within 3 months)
• Substance abuse or alcohol dependence
• Inability to comply with study procedures

Additional Exclusion for Healthy Volunteers:

• Any cognitive complaints or subjective memory loss
• First-degree family history of Alzheimer's disease (optional, depending on stratification strategy)
• Use of psychoactive medications

Additional Exclusion for Alzheimer's Disease Patients:

• Diagnosis of mixed or atypical dementia
• Rapidly progressive cognitive decline suggestive of other pathology
• Contraindications to lumbar puncture (if CSF sampling is planned)