A Biomarker Database to Investigate Blood-Based and Digital Biomarkers in Participants Screened for Alzheimer's Disease (Bio-Hermes)

Inclusion Criteria: Participants must meet all the following criteria for entry into the study: 1. Participants must provide written consent in the IRB-approved informed consent form or have a Legally Authorized Representative (LAR) provide written consent in the IRB-approved consent form on the participant's behalf; 2. Male or female 60 to 85 years of age (inclusive) at the time of consent; 3. Participants must be willing to undergo an amyloid PET scan within 60 days of signing informed consent; or for sites that do not have access to PET imaging, the participant must be willing to undergo a lumbar puncture for cerebrospinal fluid (CSF) collection within 30 days of the coagulation panel; 4. Participants must have a study partner who, in the investigator's judgement, has sufficient and frequent contact (defined as at least 8 hours of contact a week) with the participant and is able to provide accurate information regarding the participant's cognitive and functional abilities; 5. Participants must be willing to comply with all study procedures as outlined in the informed consent, including blood sampling; 6. Fluency in the language of the tests used at the study site; 7. Participants must be willing to be contacted for possible participation in clinical research trials once their participation in this study ends; and 8. Participants must have a Mini-Mental State Exam (MMSE) score of 17 to 30 inclusive at screening; those with a score of 17-19 must have a diagnosis of Probable AD. Exclusion Criteria Participants who meet any of the following criteria will not be eligible for entry into the study: 1. Participants who, in the opinion of the Site Principal Investigator, have serious or unstable medical conditions that would prohibit their completion of all study procedures and data collection; 2. Participants who have serious or unstable medical conditions that would likely preclude their participation in an interventional research trial; 3. Participants who are unable to undergo amyloid PET due to self-reported pregnancy, sensitivity of ligands being used, poor venous access, contraindication to PET, or planned or recent exposure to ionizing radiation that in combination with the planned administration of amyloid radioligand would result in a cumulative exposure that exceeds recommended local guidelines; 4. Participants who have reported or have a known negative amyloid PET scan in past 12 months; 5. Participants with self-reported, untreated conditions such as vitamin B12 or folate deficiency or bladder infections that in the opinion of the Site Principal Investigator could contribute to cognitive impairment; 6. Participants with history of stroke or seizures within 1 year of the Visit 1 (Screening); 7. Participants with history of cancer within the past 5 years with the exception of non-melanoma skin cancer or prostate cancer in situ; 8. Participants with known or suspected alcohol or drug abuse or dependence within 1 year of the Visit 1 (Screening); 9. Participants who report any current unstable psychiatric symptoms that could interfere with study procedures or impact study data (e.g., uncontrolled depression); 10. Participants who have participated in a clinical trial of any potential disease modifying AD treatment and received active drug within 6 months prior to Visit 1 (Screening); 11. Participants who have completed clinical or observational study procedures (e.g., imaging, cognitive testing) within 3 months of Visit 1 (Screening); 12. Participants who have any neurological disorder affecting the central nervous system, other than AD, that may be contributing to cognitive impairment (e.g., Parkinson's disease, other dementias, multiple concussions or seizures) as deemed significant by the Site Principal Investigator; 13. Participants with a Geriatric Depression Scale (GDS) score greater than or equal to 8 at Visit 1 (Screening); 14. Participants with a RAVLT-Delayed Recall Score of 1.5 standard deviation above the age-adjusted mean; 15. Participants with known history or self-report to be Human Immunodeficiency Virus (HIV) Positive; 16. Participants weighing less than 110 pounds; 17. Participants that have previously been consented to this study unless prior approval was granted by the Sponsor on a case-by-case basis; 18. Participants who are direct employees or family members of direct employees of the participating investigators' sites; 19. Participants who are direct employees of the Sponsor; 20. Participants who, in the opinion of the investigator, are unable to complete cognitive testing due to inadequate visual or auditory acuity; 21. For participants of the RetiSpec retinal substudy only: Those with a known history of ocular diseases (such as retinopathy, age-related macular degeneration, and glaucoma), with the exception of mild to moderate cataracts, and/or vision correction with glasses/contact lenses; 22. For participants undergoing LP: contraindication to lumbar puncture, including coagulopathy, concomitant anticoagulation (except for a platelet inhibitor such as aspirin or clopidogrel), thrombocytopenia, prior lumbar spinal surgery, significant deformity of the lumbosacral region, INR results \> 1.3, or other factor that precludes safe LP in the opinion of the Site Principal Investigator.