NCAM1 and Alzheimer disease: Following successful characterization, we evaluated the assay's ability to differentiate AD patients from HCs by testing CSF samples from a study cohort of 15 AD patients and 15 HCs, achieving AUROCs of 0.956 and 0.969 for L1CAM(+)‐NEVs and NCAM(+)‐NEVs, respectively.