Can a simple blood test catch Alzheimer's before symptoms start?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Age 50-80 2. Individuals aged 50-60 require at least one of the following risk factors for AD: 1. Known apolipoprotein E (APOE) -ε4 carrier 2. Known 1st degree family history of dementia or severe memory loss with onset prior to 75. 3. Known amyloid brain pathology by either CSF or PET scan. 3. Mini-Mental State Examination (MMSE) ≥26 (aged \>65); MMSE ≥27 (aged 50-65). 4. Score of 12 or above on the Montreal Cognitive Assessment (MoCA) telephone version. 5. Speaks and understands Swedish to the extent that an interpreter is not necessary to fully understand the study information and cognitive tests. 6a. Preclinical Alzheimer's disease subgroup (n=450): Amyloid pathology according to cerebrospinal fluid Alzheimer's disease and amyloid PET scans. 6b. Non-Preclinical Alzheimer's disease subgroup (n=150): No sign of preclinical Alzheimer's disease using cerebrospinal fluid Alzheimer's disease biomarkers or Aβ-PET scans. Exclusion Criteria: 1. Fulfils the criteria for minor or major neurocognitive disorder according to The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). 2. History of significant brain injury or other known neurologic disease or insult, resulting in lasting cognitive sequelae that would confound the assessment and staging of potential neurodegenerative disease. 3. Major depression, bipolar disorder, or recurrent psychotic disorders within the past year. 4. History of alcohol and/or substance abuse or dependence within the past year. 5. Significant unstable systemic illness or organ failure, such as terminal cancer, that makes it difficult to participate in the study. 6. Refusing or unable to complete baseline cognitive and biomarker assessments (i.e., cognitive testing, blood draw, MRI and PET).