We assessed diagnostic classification using AD‐PRS excluding APOE (AD‐PRSnoAPOE), APOE risk score (APOE‐RS), and plasma phosphorylated tau 181 (p‐tau181), in 83 participants with LBD, 27 with positron emission tomography amyloid beta (Aβ)positive mild cognitive impairment or AD (MCI+/AD), and 57 controls. This evidence concerns the gene APOE and Alzheimer disease.