The APOLLO study is a retrospective and multi-center study to validate multiomics Alzheimer's signals in the plasma of people with and without Alzheimer's. The biomarkers have already been pre-identified in a brand-new rat model (Audrain et al., (2018) Cereb Cortex). The study will include approximately 750 plasma samples across 6 sites in the United States, France, Spain and Australia. The control group consists of healthy individuals, without cognitive impairment, and other dementias excluding Alzheimer’s. The Alzheimer’s group consists of patients sampled in asymptomatic, prodromal and dementia phases. Patients have been followed up to 15 years until their conversion to dementia.